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1##############################################################################
2#                                                                            #
3#                        Powder CIF Dictionary                               #
4#                        ---------------------                               #
5#                                                                            #
6#  CIF data definitions specifically for powder diffraction applications.    #
7#  These are in addition to those defined in the Core CIF Dictionary 1996.   #
8#                                                                            #
9#  The DDL commands used in this dictionary are defined in "ddl_core.dic".   #
10#                                                                            #
11##############################################################################
12
13data_on_this_dictionary
14
15    _dictionary_name            cif_pd.dic
16    _dictionary_version         1.0
17    _dictionary_update          1997-10-29
18    _dictionary_history
19;
20  1991-08-28  Initial definitions                                  B.H. Toby
21  1991-09-15  More definitions added                               B.H. Toby
22  1991-09-21  Still More definitions                               B.H. Toby
23  1991-09-24  Some updates from down under  |:-)                   S.R. Hall
24  1991-10-07  Unable to leave well enough alone...                 B.H. Toby
25  1991-10-10  Some additional fine tuning   (-:|                   S.R. Hall
26  1991-10-14  Minor touchups                                       B.H. Toby
27  1991-12-08  Back to Work...                                      B.H. Toby
28  1992-01-07  Add _pd_refln_ to allow for mixtures                 B.H. Toby
29  1992-02-07  Some redefinitions                                   S.R. Hall
30  1992-02-25  Defining standards is a fiddly business              S.R. Hall
31  1992-03-18  And still more...                                    B.H. Toby
32  1992-05-22  Minor cleanup                                        B.H. Toby
33  1992-05-23  Quasar says that all is OK now...                    S.R. Hall
34  1992-05-30  Changes from comments @ APD-II                       B.H. Toby
35  1992-08-18  Add calculated pattern definitions                   B.H. Toby
36  1992-08-28  Change 'powder' to 'pw'                              B.H. Toby
37  1992-08-31  Major overhaul of some definitions                   B.H. Toby
38  1992-09-01  Small adjustments                                    S.R. Hall
39  1992-10-01  Change 'pw' to 'pd'                                  B.H. Toby
40  1993-04-16  Change usage for multiple detectors                  B.H. Toby
41  1993-04-19  Change *_raw_ to *_meas_; *_sample_ to *_samp_
42              Install new DDL commands; new *_phase_ group         S.R. Hall
43  1993-05-22  Fix _pd_calib_ defs; Minor editing                   B.H. Toby
44  1993-05-31  Still more minor editing                             B.H. Toby
45  1993-06-02  Application of new DDL commands                      S.R. Hall
46  1993-08-13  Last stop before Bejing, more descriptive entries &
47              more descriptive text added; support for film data.  B.H. Toby
48  1993-10-27  My two cents worth                                   I.D. Brown
49  1994-01-23  Change two to 2.5; sample to specimen.               B.H. Toby
50  1994-03-13  Change date/time usage
51              Be more careful about pd_proc usage: separate data
52              & processing conditions                              B.H. Toby
53  1994-04-11  Start work on categories: move all diffractogram
54              items (that might ever be in a single loop) into
55              pd_data.                                             B.H. Toby
56  1994-05-11  Start revisions based on I.D. Brown's comments       B.H. Toby
57  1994-06-25  Complete revisions prior to ACA                      B.H. Toby
58  1994-10-27  Working draft                                        B.H. Toby
59  1995-10-23  Implemented _units and _units_detail                 B. McMahon
60  1995-10-24  Transferred _pd_instr_radiation_probe to the core
61              as _diffrn_radiation_probe                           B. McMahon
62  1997-01-30  Final cleanup: removed _nm units; add units to
63              definitions; add _pd_block_diffractogram_id;
64              change _pd_meas_distance_value to _pd_meas_position;
65              remove _pd_proc_wavelength_nm, _pd_proc_d_spacing_nm;
66              _pd_proc_recip_len_Q_nm, and _pd_peak_d_spacing_nm
67                                                                   B.H. Toby
68  1997-01-31  Changed dictionary_definition to category_overview;
69              removed data_include_dependent_dictionaries and global_
70              blocks; some typos fixed                             B. McMahon
71  1997-02-12  Some typos fixed                                     B. McMahon
72  1997-02-18  References to e.s.d. changed to s.u. etc.
73              Notation for Bragg and expected R factors changed to
74              R~B~ and R~exp~
75                                                                   B. McMahon
76  1997-03-10  Category of _pd_refln_ things changed to 'refln'; category of`
77              _pd_proc_number_of_points changed to 'pd_proc_info'; some
78              rewording of descriptions involving s.u.s according to BT;
79              changed 'samp' to 'spec' in many datanames relating distances
80              to specimen; changed style of these and similar to *_src/spec
81              etc; _pd_calc_method no longer has '_list yes'; _list_uniqueness
82              deleted from _pd_refln_peak_id; use of '.' instead of '?'
83              recommended in a couple of places; addition of example to
84              _pd_calib_conversion_eqn; '_pd_proc_intensity_calc_bkg' and
85              '_fix_bkg' changed to '_pd_proc_intensity_bkg_calc' and '_fix'
86                                                                   B. McMahon
87  1997-03-12  Category of _pd_calib_ things changed to 'pd_calib';
88              _pd_calib_conversion_eqn and *_special_details renamed as
89              _pd_calibration_* and assigned to category 'pd_calibration'
90              Alphabetised entries within category.
91                                                                   B. McMahon
92  1997-03-17  Copyediting changes to punctuation and spelling.     B. McMahon
93  1997-10-29  Changed _pd_calib_std_external_id to
94              _pd_calib_std_external_block_id. Moved _pd_proc_2theta_range_ to
95              category pd_proc_info (because not looped with other pd_data
96              items).
97                                                                   B. McMahon
98  1997-10-29  Release version 1.0                                  B. McMahon
99;
100
101#......................... Block/Dataset names
102
103data_pd_block_[pd]
104    _name                       '_pd_block_[pd]'
105    _category                     category_overview
106    _type                         null
107    _definition
108;              _pd_block_id is used to assign a unique id code to a data block.
109               This code is then used for references between different blocks
110               (see _pd_block_diffractogram_id, _pd_calib_std_external_block_id
111               and _pd_phase_block_id).
112
113               Note that a data block may contain only a single diffraction
114               dataset or information about a single crystalline phase. Yet a
115               single diffraction measurement may yield structural information
116               on more than one phase, or a single structural determination may
117               use more than one dataset. Alternatively, results from a single
118               dataset, such as calibration parameters from measurements of a
119               standard, may be used for many subsequent analyses. Through use
120               of the id code, a reference made between datasets may be
121               preserved when the file is exported from the laboratory where
122               the CIF originated.
123
124               The id code assigned to each data block should be unique with
125               respect to an id code assigned for any other data block in the
126               world. The naming scheme chosen for the block-id format is
127               designed to ensure uniqueness.
128
129               It is the responsibility of a data archive site or local
130               laboratory to create a catalogue of block id's, if that site
131               wishes to resolve these references.
132;
133
134data_pd_block_diffractogram_id
135    _name                      '_pd_block_diffractogram_id'
136    _category                    pd_proc
137    _type                        char
138    _list                        yes
139    _definition
140;              A block id code (see _pd_block_id) that identifies
141               diffraction data contained in a data block other
142               than the current block. This will most frequently
143               occur when more than one set of diffraction data
144               is used for a structural determination. The data
145               block containing the diffraction data will contain
146               a _pd_block_id code matching the code in
147               _pd_block_diffractogram_id.
148;
149
150data_pd_block_id
151    _name                      '_pd_block_id'
152    _category                    pd_block
153    _type                        char
154    _list                        both
155    loop_ _example
156                         1991-15-09T16:54|Si-std|B.Toby|D500#1234-987
157                         1991-15-09T16:54|SEPD7234|B.Toby|SEPD.IPNS.ANL.GOV
158    _definition
159;              Used to assign a unique character string to a block.
160               Note that this code is not intended to be parsed; the
161               concatenation of several strings is used in order to
162               generate a string that can reasonably be expected to
163               be unique.
164
165               This code is assigned by the originator of the dataset and
166               is used for references between different CIF blocks.
167               The id will normally be created when the block is first
168               created. It is possible to loop more than one id for a
169               block: if changes or additions are later made to the
170               block, a new id may be assigned, but the original name
171               should be retained.
172
173               The format for the id code is:
174                 <date-time>|<block_name>|<creator_name>|<instr_name>
175
176                <date-time>    is the date and time the CIF was created
177                               or modified.
178
179                <block_name>   is an arbitrary name assigned by the
180                               originator of the dataset. It will
181                               usually match the name of the phase
182                               and possibly the name of the current CIF
183                               data block (i.e. the string xxxx in a
184                               data_xxxx identifier). It may be a sample name.
185
186                <creator_name> is the name of the person who measured the
187                               diffractogram, prepared or modified the CIF.
188
189                <instr_name>  is a unique name (so far as possible) for
190                               the data collection instrument, preferably
191                               containing the instrument serial number for
192                               commercial instruments. It is also possible to
193                               use the Internet name or address for the
194                               instrument computer as a unique name.
195
196               As blocks are created in a CIF, the original sample identifier
197               (i.e. <block_name>) should be retained, but the <creator_name>
198               may be changed and the <date-time> will always change.
199               The <date-time> will usually match either the
200               _pd_meas_datetime_initiated or the _pd_proc_info_datetime
201               entry.
202
203               Within each section of the code, the following characters
204               may be used:
205                             A-Z a-z 0-9 # & * . : , - _ + / ( ) \ [ ]
206
207               The sections are separated with vertical bars '|' which are
208               not allowed within the sections. Blank spaces may also
209               not be used.  Capitalisation be may used within the id code
210               but should not be considered significant - searches for
211               dataset id names should be case insensitive.
212
213               Date-time entries are in the standard CIF format
214               'yyyy-mm-ddThh:mm:ss+zz' Use of seconds and a time zone
215               is optional, but use of hours and minutes is strongly
216               encouraged as this will help ensure that the id code is unique.
217
218               An archive site that wishes to make CIF files available via
219               WWW may substitute the URL for the file containing the
220               appropriate block for the final two sections of the id
221               (<creator_name> and <instr_name>). Note that this should
222               not be done unless the archive site is prepared to keep the
223               file available on-line indefinitely.
224;
225
226#......................... Measured Diffractogram Information
227
228data_pd_meas_[pd]
229    _name                     '_pd_meas_[pd]'
230    _category                   category_overview
231    _type                       null
232    loop_
233        _example
234        _example_detail
235#----------------------------------------------------------------------------
236;
237    _pd_meas_info_author_name        'Cranswick, Lachlan'
238    _pd_meas_info_author_email       lachlan@dmp.csiro.au
239    _pd_meas_info_author_address     ?
240    _pd_meas_datetime_initiated      1992-03-23T17:20
241
242    _pd_meas_scan_method             step
243    _pd_meas_2theta_range_min        6.0
244    _pd_meas_2theta_range_max        164.0
245    _pd_meas_2theta_range_inc        0.025
246    _pd_meas_step_count_time         2.0
247;
248;
249    Example 1
250;
251#----------------------------------------------------------------------------
252    _definition
253;              This section contains the measured diffractogram and information
254               about conditions used for measurement of the diffraction dataset,
255               prior to processing and application of correction terms. While
256               additional information may be added to the CIF as data are
257               processed and transported between laboratories (possibly with
258               addition of a new _pd_block_id entry), the information in this
259               section of the CIF will rarely be changed once data collection is
260               complete.
261
262               Where possible, measurements in this section should have no
263               post-collection processing applied (normalisations, corrections,
264               smoothing, zero-offset corrections, etc.). Such corrected
265               measurements should be recorded in the _pd_proc_ section.
266
267               Datasets that are measured as counts, where a standard
268               uncertainty can be considered equivalent to the standard
269               deviation and where the standard deviation can be estimated
270               as the square root of the number of counts recorded, should
271               use the _pd_meas_counts_ fields. All other intensity values
272               should be recorded using _pd_meas_intensity_.
273;
274
275data_pd_meas_2theta_fixed
276    _name                      '_pd_meas_2theta_fixed'
277    _category                    pd_meas_method
278    _type                        numb
279    _type_conditions             esd
280    _enumeration_range           -180.0:360.0
281    _definition
282;              The 2\q diffraction angle in degrees for measurements
283               in a white-beam fixed-angle experiment. For measurements
284               where 2\q is scanned see _pd_meas_2theta_scan or
285               _pd_meas_2theta_range_.
286;
287
288data_pd_meas_2theta_range_
289    loop_ _name                '_pd_meas_2theta_range_min'
290                               '_pd_meas_2theta_range_max'
291                               '_pd_meas_2theta_range_inc'
292    _category                    pd_meas_method
293    _type                        numb
294    _enumeration_range           -180.0:360.0
295    _definition
296;              The range of 2\q diffraction angles in degrees for the
297               measurement of intensities. These may be used in place of the
298               _pd_meas_2theta_scan values for datasets measured with a
299               constant step size.
300;
301
302data_pd_meas_2theta_scan
303    _name                      '_pd_meas_2theta_scan'
304    _category                    pd_data
305    _type                        numb
306    _type_conditions             esd
307    _list                        yes
308    _enumeration_range           -180.0:360.0
309    _definition
310;              2\q diffraction angle (in degrees) for intensity
311               points measured in a scanning method. The scan method used
312               (e.g. continuous or step scan) should be specified in
313               item _pd_meas_scan_method. For fixed 2\q (white-beam)
314               experiments, use _pd_meas_2theta_fixed. In the case of
315               continuous scan datasets, the 2\q value should be the
316               value at the mid-point of the counting period. Associated
317               with each _pd_meas_2theta_scan value will be
318               _pd_meas_counts_ items. The 2\q values should
319               not be corrected for non-linearity,
320               zero offset, etc. Corrected values may be specified
321               using _pd_proc_2theta_corrected.
322
323               Note that for datasets taken with constant step size,
324               _pd_meas_2theta_range_ (*_min, *_max, and *_inc) may be
325               used instead of _pd_meas_2theta_scan.
326;
327
328data_pd_meas_angle_
329    loop_ _name                '_pd_meas_angle_chi'
330                               '_pd_meas_angle_omega'
331                               '_pd_meas_angle_phi'
332                               '_pd_meas_angle_2theta'
333    _category                    pd_data
334    _type                        numb
335    _list                        both
336    _enumeration_range           -180.0:360.0
337    _definition
338;              The diffractometer angles in degrees for an instrument
339               with an Euler circle. The definitions for these angles
340               follow the convention of International Tables for
341               X-ray Crystallography, Vol. IV (1974), p. 276.
342;
343
344data_pd_meas_counts_
345    loop_ _name                '_pd_meas_counts_total'
346                               '_pd_meas_counts_background'
347                               '_pd_meas_counts_container'
348                               '_pd_meas_counts_monitor'
349    _category                    pd_data
350    _type                        numb
351    _list                        yes
352    _enumeration_range           0:
353    _definition
354;              Counts measured at the measurement point as a function of
355               angle, time, channel, or some other variable (see
356               _pd_meas_2theta_ ...).
357
358               The defined fields are:
359                 _pd_meas_counts_total: scattering from the specimen
360                   (with background, specimen mounting or container
361                   scattering included);
362                 _pd_meas_counts_background: scattering measured
363                   without a specimen, specimen mounting, etc., often
364                   referred to as the instrument background;
365                 _pd_meas_counts_container: the specimen container or
366                   mounting without a specimen, includes background;
367                 _pd_meas_counts_monitor: counts measured by an incident
368                   beam monitor to calibrate the flux on the specimen.
369
370               Corrections for background, detector deadtime, etc.,
371               should not have been made to these values. Instead use
372               _pd_proc_intensity_ for corrected diffractograms.
373
374               Note that counts-per-second values should be converted to
375               total counts. If the counting time varies for different
376               points, it may be included in the loop using
377               _pd_meas_step_count_time.
378
379               Standard uncertainties should not be quoted for these values.
380               If the standard uncertainties differ from the square root of
381               the number of counts, _pd_meas_intensity_ should be used.
382;
383
384data_pd_meas_datetime_initiated
385    _name                      '_pd_meas_datetime_initiated'
386    _category                    pd_meas_method
387    _type                        char
388    _example                     1990-07-13T14:40
389    _definition
390;              The date and time of the dataset measurement. Entries follow
391               the standard CIF format 'yyyy-mm-ddThh:mm:ss+zz'. Use
392               of seconds and a time zone is optional, but use of hours
393               and minutes is strongly encouraged. Where possible give the
394               time when the measurement was started rather than when
395               completed.
396;
397
398data_pd_meas_detector_id
399    _name                      '_pd_meas_detector_id'
400    _category                    pd_data
401    _type                        char
402    _list                        yes
403    _list_link_parent          '_pd_calib_detector_id'
404    _definition
405;              A code or number which identifies the measuring detector or
406               channel number in a position-sensitive, energy-dispersive
407               or other multiple-detector instrument.
408
409               Calibration information, such as angle offsets,
410               a calibration function to convert channel numbers
411               to Q, energy, wavelength, angle, etc. should
412               be described with _pd_calib_ values. If
413               _pd_calibration_conversion_eqn is used, the detector id's
414               should be the number to be used in the equation.
415;
416
417data_pd_meas_info_author_address
418    _name                      '_pd_meas_info_author_address'
419    _category                    pd_meas_info
420    _type                        char
421    _list                        both
422    _list_reference            '_pd_meas_info_author_name'
423    _definition
424;              The address of the person who measured the dataset. If there
425               is more than one person this will be looped with
426               _pd_meas_info_author_name.
427;
428
429data_pd_meas_info_author_email
430    _name                      '_pd_meas_info_author_email'
431    _category                    pd_meas_info
432    _type                        char
433    _list                        both
434    _list_reference            '_pd_meas_info_author_name'
435    _definition
436;              The email address of the person who measured the dataset. If
437               there is more than one person this will be looped with
438               _pd_meas_info_author_name.
439;
440
441data_pd_meas_info_author_fax
442    _name                      '_pd_meas_info_author_fax'
443    _category                    pd_meas_info
444    _type                        char
445    _list                        both
446    _list_reference            '_pd_meas_info_author_name'
447    _definition
448;              The fax number of the person who measured the dataset. If
449               there is more than one person this will be looped with
450               _pd_meas_info_author_name. The recommended style includes
451               the international dialing prefix, the area code in
452               parentheses, followed by the local number with no spaces.
453;
454
455data_pd_meas_info_author_name
456    _name                      '_pd_meas_info_author_name'
457    _category                    pd_meas_info
458    _type                        char
459    _list                        both
460    _definition
461;              The name of the person who measured the dataset. The family
462               name(s), followed by a comma and including any dynastic
463               components, precedes the first name(s) or initial(s).
464               For more than one person use a loop to specify multiple values.
465;
466
467data_pd_meas_info_author_phone
468    _name                      '_pd_meas_info_author_phone'
469    _category                    pd_meas_info
470    _type                        char
471    _list                        both
472    _list_reference            '_pd_meas_info_author_name'
473    _definition
474;              The telephone number of the person who measured the dataset.
475               If there is more than one person this will be looped with
476               _pd_meas_info_author_name. The recommended style includes
477               the international dialing prefix, the area code in
478               parentheses, followed by the local number with no spaces.
479;
480
481data_pd_meas_intensity_
482    loop_ _name                '_pd_meas_intensity_total'
483                               '_pd_meas_intensity_background'
484                               '_pd_meas_intensity_container'
485                               '_pd_meas_intensity_monitor'
486    _category                    pd_data
487    _type                        numb
488    _type_conditions             esd
489    _list                        yes
490    _definition
491;              Intensity measurements at the measurement point (see
492               the definition of _pd_meas_2theta_).
493
494               The defined fields are:
495                 _pd_meas_intensity_total: scattering from the specimen
496                   (with background, specimen mounting or container
497                   scattering included);
498                 _pd_meas_intensity_background: scattering measured
499                   without a specimen, specimen mounting, etc., often
500                   referred to as the instrument background;
501                 _pd_meas_intensity_container: the specimen container or
502                   mounting without a specimen, includes background;
503                 _pd_meas_intensity_monitor: intensity measured by an
504                   incident beam monitor to calibrate the flux on the specimen.
505
506               Use these entries for measurements where intensity
507               values are not counts (use _pd_meas_counts_ for event-counting
508               measurements where the standard uncertainty is
509               estimated as the square root of the number of counts).
510
511               Corrections for background, detector deadtime, etc.,
512               should not have been made to these values. Instead use
513               _pd_proc_intensity_ for corrected diffractograms.
514
515               _pd_meas_units_of_intensity should be used to specify
516               the units of the intensity measurements.
517;
518
519data_pd_meas_number_of_points
520    _name                      '_pd_meas_number_of_points'
521    _category                    pd_meas_method
522    _type                        numb
523    _enumeration_range           1:
524    _definition
525;              The total number of points in the measured
526               diffractogram.
527;
528
529data_pd_meas_position
530    _name                      '_pd_meas_position'
531    _category                    pd_data
532    _type                        numb
533    _type_conditions             esd
534    _list                        yes
535    _units                       mm
536    _units_detail               'millimetres'
537    _definition
538;              A linear distance in millimetres corresponding to the
539               location where an intensity measurement is made.
540               Used for detectors where a distance measurement is made
541               as a direct observable - such as from a microdensitometer
542               trace from film or a strip chart recorder. This is an
543               alternative to _pd_meas_2theta_scan, which should only be
544               used for instruments that record intensities directly
545               against 2\q. For instruments where the position scale
546               is non-linear, data item _pd_meas_detector_id should
547               be used to record positions.
548
549               Calibration information, such as angle offsets or a
550               function to convert this distance to a 2\q angle
551               or d-space, should be supplied with the _pd_calib_ values.
552
553               Do not confuse this with the instrument geometry
554               descriptions given by _pd_instr_dist_.
555;
556
557data_pd_meas_rocking_angle
558    _name                      '_pd_meas_rocking_angle'
559    _category                    pd_data
560    _type                        numb
561    _list                        both
562    _units                       deg
563    _units_detail               'degrees'
564    _enumeration_range           0:360.0
565    _definition
566;              The angular range in degrees a sample is rotated
567               or oscillated during a measurement step
568               (see _pd_meas_rocking_axis).
569;
570
571data_pd_meas_rocking_axis
572    _name                      '_pd_meas_rocking_axis'
573    _category                    pd_meas_method
574    _type                        char
575    _list                        both
576    loop_ _enumeration           chi
577                                 omega
578                                 phi
579    _definition
580;              Description of the axis (or axes) used to rotate or rock the
581               specimen for better randomisation of crystallites
582               (see _pd_meas_rocking_angle).
583;
584
585data_pd_meas_scan_method
586    _name                      '_pd_meas_scan_method'
587    _category                    pd_meas_method
588    _type                        char
589    loop_ _enumeration
590          _enumeration_detail    step    'step scan'
591                                 cont    'continuous scan'
592                                 tof     'time of flight'
593                                 disp    'energy-dispersive'
594                                 fixed   'stationary detector'
595    _definition
596;              Code identifying the method for scanning reciprocal space.
597               The designation `fixed' should be used for measurements where
598               film, a stationary position-sensitive or area detector
599               or other non-moving detection mechanism is used to
600               measure diffraction intensities.
601;
602
603data_pd_meas_special_details
604    _name                      '_pd_meas_special_details'
605    _category                    pd_meas_method
606    _type                        char
607    _definition
608;              Special details of the diffraction measurement process.
609               Include information about source instability, degradation, etc.
610               However, this item should not be used to record information
611               that can be specified in other _pd_meas_ entries.
612;
613
614data_pd_meas_step_count_time
615    _name                      '_pd_meas_step_count_time'
616    _category                    pd_data
617    _type                        numb
618    _type_conditions             esd
619    _list                        both
620    _units                       s
621    _units_detail               'seconds'
622    _enumeration_range           0.0:
623    _definition
624;              The count time in seconds for each intensity measurement.
625               If this value varies for different intensity measurements,
626               then this item will be placed in the loop with the
627               diffraction measurements. If a single fixed value is used,
628               it may be recorded outside the loop.
629;
630
631data_pd_meas_time_of_flight
632    _name                      '_pd_meas_time_of_flight'
633    _category                    pd_data
634    _type                        numb
635    _type_conditions             esd
636    _list                        yes
637    _units                       \ms
638    _units_detail               'microseconds'
639    _enumeration_range           0:
640    _definition
641;              Measured time in microseconds for time-of-flight neutron
642               measurements. Note that the flight distance may be
643               specified using _pd_instr_dist_ values.
644;
645
646data_pd_meas_units_of_intensity
647    _name                      '_pd_meas_units_of_intensity'
648    _category                    pd_meas_method
649    _type                        char
650    _list                        no
651    loop_ _example        'estimated from strip chart'
652                          'arbitrary, from film density'
653                          'counts, with automatic deadtime correction applied'
654    _definition
655;              Units for intensity measurements when _pd_meas_intensity_
656               is used. Note that use of 'counts' or 'counts per second'
657               here is to be strongly discouraged - convert the intensity
658               measurements to counts and use _pd_meas_counts_ and
659               _pd_meas_step_count_time instead of _pd_meas_intensity_.
660;
661
662#........................... Calibration Information
663
664data_pd_calib_[pd]
665    _name                       '_pd_calib_[pd]'
666    _category                     category_overview
667    _type                         null
668    loop_
669        _example
670        _example_detail
671#----------------------------------------------------------------------------
672;
673   _pd_calib_std_external_block_id
674                          QuartzPlate|D500#1234-987|B.Toby|91-15-09|14:02
675   _pd_calib_std_external_name
676                          'Arkansas Stone quartz plate'
677;
678;
679    Example 1
680;
681;
682    _pd_calibration_conversion_eqn
683    ; 2\q~actual~ = 2\q~setting~ + arctan(
684             cos(P~1~) / (1/(P~0~ (CC - CH~0~ - P~2~ CC^2^)) - sin(P~1~)) )
685    ;
686;
687;
688    Example 2 -
689                2\q~actual~ = 2\q~setting~ + arctan( cos(P~1~) / (1/(P~0~
690                  (CC - CH~0~ - P~2~ CC^2^)) - sin(P~1~)) )
691
692                This allows for the calibration of 2\q for a linear
693                position-sensitive detector (PSD) where the PSD has been
694                set so that the 'centre channel' (CH~0~) is located at
695                2\q~setting~ as a function of the channel number (CC). In
696                addition to CH~0~, variables P~0~, P~1~ and P~2~ are
697                calibration constants, where P~0~ is the width of a PSD
698                channel in degrees, P~1~ is the angle of the PSD with respect
699                to the perpendicular and P~2~ is a quadratic term for
700                non-linearities in the detector.
701;
702#----------------------------------------------------------------------------
703    _definition
704;              This section defines parameters used for calibration of the
705               instrument used directly or indirectly in the interpretation
706               of this dataset. The information in this section of the CIF
707               should generally be written when the intensities are first
708               measured, but from then on should remain unchanged. Loops may
709               be used for calibration information that differs by detector
710               channel. The _pd_calibration_ items, however, are never looped.
711;
712
713data_pd_calib_2theta_
714    loop_ _name                '_pd_calib_2theta_offset'
715                               '_pd_calib_2theta_off_point'
716                               '_pd_calib_2theta_off_min'
717                               '_pd_calib_2theta_off_max'
718    _category                    pd_calib
719    _type                        numb
720    _list                        both
721    _list_reference            '_pd_calib_detector_id'
722    _units                       deg
723    _units_detail               'degrees'
724    _enumeration_range           -180.0:180.0
725    _definition
726;              _pd_calib_2theta_offset defines an offset angle (in degrees)
727               used to calibrate 2\q (as defined in _pd_meas_2theta_).
728               Calibration is done by adding the offset:
729
730                    2\q~calibrated~ = 2\q~measured~ + 2\q~offset~
731
732               For cases where the _pd_calib_2theta_offset value is
733               not a constant, but rather varies with 2\q, a set
734               of offset values can be supplied in a loop. In this case,
735               the value where the offset has been determined can be
736               specified as _pd_calib_2theta_off_point. Alternatively a
737               range where the offset is applicable can be specified using
738               _pd_calib_2theta_off_min and _pd_calib_2theta_off_max.
739;
740
741data_pd_calib_detector_id
742    _name                      '_pd_calib_detector_id'
743    _category                    pd_calib
744    _type                        char
745    _list                        yes
746    _list_mandatory              yes
747    _list_link_child           '_pd_meas_detector_id'
748    _definition
749;              A code which identifies the detector or channel number in a
750               position-sensitive, energy-dispersive or other multiple-detector
751               instrument. Note that this code should match the code name used
752               for _pd_meas_detector_id.
753;
754
755data_pd_calib_detector_response
756    _name                      '_pd_calib_detector_response'
757    _category                    pd_calib
758    _type                        numb
759    _list                        yes
760    _list_reference            '_pd_calib_detector_id'
761    _enumeration_range           0.0:
762    _definition
763;              A value that indicates the relative sensitivity of each
764               detector. This can compensate for differences in electronics,
765               size and collimation. Usually, one detector or the mean for
766               all detectors will be assigned the value of 1.
767;
768
769data_pd_calib_std_external_
770    loop_ _name                '_pd_calib_std_external_block_id'
771                               '_pd_calib_std_external_name'
772    _category                    pd_calib
773    _type                        char
774    _list                        both
775    _list_reference            '_pd_calib_detector_id'
776    _definition
777;              Identifies the dataset used as an external standard for
778               the diffraction angle or the intensity calibrations.
779               *_name specifies the name of the material and
780               *_id the _pd_block_id for the CIF containing calibration
781               measurements. If more than one dataset is used for
782               calibration, these fields may be looped.
783;
784
785data_pd_calib_std_internal_mass_%
786    _name                      '_pd_calib_std_internal_mass_%'
787    _category                    pd_calib
788    _type                        numb
789    _type_conditions             esd
790    _list                        both
791    _list_reference            '_pd_calib_detector_id'
792    _enumeration_range           0.0:100.0
793    _definition
794;              Percent presence of the internal standard specified by the
795               data item _pd_calib_std_internal_name expressed as 100 times
796               the ratio of the amount of standard added to the original
797               sample mass.
798;
799
800data_pd_calib_std_internal_name
801    _name                      '_pd_calib_std_internal_name'
802    _category                    pd_calib
803    _type                        char
804    _list                        both
805    _list_reference            '_pd_calib_detector_id'
806    loop_ _example              'NIST 640a Silicon standard'
807                                'Al2O3'
808    _definition
809;              Identity of material(s) used as an internal intensity standard.
810;
811
812data_pd_calibration_conversion_eqn
813    _name                      '_pd_calibration_conversion_eqn'
814    _category                    pd_calibration
815    _type                        char
816    _example
817; 2\q~actual~ = 2\q~setting~ + arctan(
818             cos(P~1~) / (1/(P~0~ (CC - CH~0~ - P~2~ CC^2^)) - sin(P~1~)) )
819;
820    _definition
821;              The calibration function to convert a channel number
822               supplied in _pd_meas_detector_id for a position-sensitive
823               or energy-dispersive detector or the distance supplied in
824               _pd_meas_position to Q, energy, angle...
825               Use _pd_calib_std_external_ to define a pointer
826               to the file or data block containing the information used
827               to define this function.
828;
829
830data_pd_calibration_special_details
831    _name                      '_pd_calibration_special_details'
832    _category                    pd_calibration
833    _type                        char
834    _definition
835;              Descriptive information about how the instrument was
836               calibrated, particularly for instruments where
837               calibration information is used to make hardware
838               settings that would otherwise be invisible once data
839               collection is completed. Do not use this item to specify
840               information that can be specified using other _pd_calib_
841               items.
842;
843
844#............................ Specimen parameters
845
846data_pd_spec_[pd]
847    _name                       '_pd_spec_[pd]'
848    _category                     category_overview
849    _type                         null
850    loop_
851        _example
852        _example_detail
853#----------------------------------------------------------------------------
854;
855    _pd_spec_mounting               ?
856    _pd_spec_mount_mode             transmission
857    _pd_spec_orientation            horizontal
858    _pd_spec_preparation            ?
859;
860;
861    Example 1
862;
863#----------------------------------------------------------------------------
864    _definition
865;              This section contains information about the specimen used
866               for measurement of the diffraction dataset. Note that information
867               about the sample (the batch of material where the specimen was
868               obtained), is specified in _pd_prep_.
869;
870
871data_pd_spec_description
872     _name                     '_pd_spec_description'
873     _category                   pd_spec
874     _type                       char
875     _definition
876;               A description of the specimen such as the source of the
877                specimen, identification of standards, mixtures, etc.
878;
879
880data_pd_spec_mount_mode
881    _name                      '_pd_spec_mount_mode'
882    _category                    pd_spec
883    _type                        char
884    loop_ _enumeration           reflection
885                                 transmission
886    _definition
887;              A code describing the beam path through the specimen.
888;
889
890data_pd_spec_mounting
891    _name                      '_pd_spec_mounting'
892    _category                    pd_spec
893    _type                        char
894    loop_ _example               'vanadium can with He exchange gas'
895                                 'quartz capillary'
896                                 'packed powder pellet'
897                                 'drifted powder on off-cut Si'
898                                 'drifted powder on Kapton film'
899    _definition
900;              A description of how the specimen is mounted.
901;
902
903data_pd_spec_orientation
904    _name                      '_pd_spec_orientation'
905    _category                    pd_spec
906    _type                        char
907    loop_ _enumeration           horizontal
908                                 vertical
909                                 both
910    _definition
911;              The orientation of the \w (\q) and 2\q axis.
912               Note that this axis is parallel to the specimen axial axis
913               and perpendicular to the plane containing the incident and
914               scattered beams.
915
916               Thus for a horizontal orientation, scattering
917               measurements are made in a plane perpendicular to the
918               ground (the 2\q axis is parallel to the ground);
919               for vertical orientation, scattering measurements are
920               made in a plane parallel with the ground (the 2\q axis
921               is perpendicular to the ground). `Both' is appropriate for
922               experiments where measurements are made in both planes,
923               for example using 2-D detectors.
924;
925
926data_pd_spec_preparation
927    _name                      '_pd_spec_preparation'
928    _category                    pd_spec
929    _type                        char
930    loop_ _example               'wet grinding in acetone'
931                              'sieved through a 44 micron (325 mesh/inch) sieve'
932                                 'spray dried in water with 1% clay'
933    _definition
934;              A description of preparation steps for producing the
935               diffraction specimen from the sample. Include any procedures
936               related to grinding, sieving, spray drying, etc. For
937               information relevant to how the sample is synthesised, use
938               the _pd_prep_ entries.
939;
940
941data_pd_spec_shape
942    _name                      '_pd_spec_shape'
943    _category                    pd_spec
944    _type                        char
945    loop_ _enumeration           cylinder
946                                 flat_sheet
947                                 irregular
948    _definition
949;              A code describing the specimen shape.
950;
951
952data_pd_spec_size_
953    loop_ _name                '_pd_spec_size_axial'
954                               '_pd_spec_size_equat'
955                               '_pd_spec_size_thick'
956    _category                    pd_spec
957    _type                        numb
958    _units                       mm
959    _units_detail               'millimetres'
960    _enumeration_range           0.0:
961    _definition
962;              The size of the specimen in three mutually perpendicular
963               directions in millimetres.
964               The perpendicular to the plane containing the incident
965               and scattered beam is the *_axial direction.
966               In transmission geometry, the scattering vector is parallel
967               to *_equat and in reflection geometry the scattering vector is
968               parallel to *_thick.
969
970;
971
972data_pd_spec_special_details
973    _name                      '_pd_spec_special_details'
974    _category                   pd_spec
975    _type                       char
976    _definition
977;              Descriptive information about the specimen that cannot be
978               included in other data items.
979;
980
981#............................ Instrument parameters
982
983data_pd_instr_[pd]
984    _name                       '_pd_instr_[pd]'
985    _category                     category_overview
986    _type                         null
987    loop_
988        _example
989        _example_detail
990#----------------------------------------------------------------------------
991;
992    _pd_instr_slit_eq_src/spec       1.
993    _pd_instr_slit_eq_anal/detc      0.2
994
995    _pd_instr_geometry              Bragg-Brentano
996    _pd_instr_monochr_post_spec     'graphite (0001)'
997    _pd_instr_cons_illum_flag       no
998;
999;
1000    Example 1
1001;
1002#----------------------------------------------------------------------------
1003    _definition
1004;              This section contains information relevant to the instrument
1005               used for the diffraction measurement. For most laboratories,
1006               very little of this information will change, so a standard file
1007               may be prepared and included with each dataset.
1008
1009               Note that several definitions in the core CIF dictionary
1010               are relevant here. For example, use:
1011                 _diffrn_radiation_wavelength for the source wavelength,
1012                 _diffrn_radiation_type for the X-ray wavelength type,
1013                 _diffrn_radiation_source for the radiation source,
1014                 _diffrn_radiation_polarisn_ratio for the source polarisation,
1015                 _diffrn_radiation_probe for the radiation type.
1016               For datasets measured with partially monochromatised radiation,
1017               for example, where both K\a~1~ and K\a~2~ are present, it is
1018               important that all wavelengths present be included using a
1019               loop_ for _diffrn_radiation_wavelength, possibly with
1020               _diffrn_radiation_wavelength_id and
1021               _diffrn_radiation_wavelength_wt. It may also be useful to
1022               create a "dummy" id to use for labeling
1023               peaks/reflections where the K\a~1~ and K\a~2~ wavelengths are
1024               not resolved. Set _diffrn_radiation_wavelength_wt to be 0 for
1025               such a dummy id.
1026
1027               In the _pd_instr_ definitions, the term monochromator refers
1028               to a primary beam (pre-specimen) monochromator and the term
1029               analyser refers to post-diffraction (post-specimen)
1030               monochromator.  The analyser may be fixed for specific
1031               wavelength or may be capable of being scanned.
1032
1033               For multiple-detector instruments it may be necessary to loop the
1034               *_anal/detc or *_spec/detc values (for  _pd_instr_dist_,
1035               _pd_instr_divg_, _pd_instr_slit_ and  _pd_instr_soller_) with
1036               the detector id's (_pd_calib_detector_id).
1037
1038               It is strongly recommended that the core dictionary term
1039               _diffrn_radiation_probe (specifying the nature of the radiation
1040               used) be employed for all datasets.
1041;
1042
1043data_pd_instr_2theta_monochr_
1044    loop_ _name                 '_pd_instr_2theta_monochr_pre'
1045                                '_pd_instr_2theta_monochr_post'
1046    _category                    pd_instr
1047    _type                        numb
1048    _list                        both
1049    _units                       deg
1050    _units_detail               'degrees'
1051    _enumeration_range           -180.0:180.0
1052    _definition
1053;              The 2\q angle for pre-specimen or post-specimen
1054               monochromator (see _pd_instr_monochr_pre_spec and
1055               _pd_instr_monochr_post_spec).
1056;
1057
1058data_pd_instr_beam_size_
1059    loop_ _name                '_pd_instr_beam_size_ax'
1060                               '_pd_instr_beam_size_eq'
1061    _category                    pd_data
1062    _type                        numb
1063    _enumeration_range           0.0:
1064    _units                       mm
1065    _units_detail               'millimetres'
1066    _definition
1067;              Axial and equatorial dimensions of the radiation beam
1068               at the specimen position (in millimetres).
1069               The perpendicular to the plane containing the incident
1070               and scattered beam is the axial (*_ax) direction.
1071;
1072
1073data_pd_instr_cons_illum_flag
1074    _name                      '_pd_instr_cons_illum_flag'
1075    _category                    pd_instr
1076    _list                        no
1077    _type                        char
1078    loop_ _enumeration           yes  no
1079    _definition
1080;              Use 'yes' for instruments where the divergence slit is
1081               \q-compensated to yield a constant illumination length
1082               (also see '_pd_instr_cons_illum_len').
1083
1084               For other flat-plate instruments, where the illumination
1085               length changes with 2\q, specify 'no'. Note that
1086               if the length is known, it may be specified using
1087               '_pd_instr_var_illum_len'.
1088;
1089
1090data_pd_instr_cons_illum_len
1091    _name                      '_pd_instr_cons_illum_len'
1092    _category                    pd_instr
1093    _list                        no
1094    _type                        numb
1095    _enumeration_range           0.0:
1096    _units                       mm
1097    _units_detail               'millimetres'
1098    _definition
1099;              Length of the specimen that is illuminated by the radiation
1100               source (in millimetres).
1101
1102               Use _pd_instr_cons_illum_len for instruments where
1103               the illumination length does not vary with 2\q, by
1104               adjustment of the divergence slits (sometimes known
1105               as \q-compensated slits).
1106               Use _pd_instr_var_illum_len for instruments where
1107               the divergence slit is fixed so that the illumination
1108               length varies with 2\q when the length is known.
1109;
1110
1111data_pd_instr_dist_
1112    loop_ _name                '_pd_instr_dist_src/mono'
1113                               '_pd_instr_dist_mono/spec'
1114                               '_pd_instr_dist_src/spec'
1115                               '_pd_instr_dist_spec/anal'
1116                               '_pd_instr_dist_anal/detc'
1117                               '_pd_instr_dist_spec/detc'
1118    _category                    pd_instr
1119    _type                        numb
1120    _units                       mm
1121    _units_detail               'millimetres'
1122    _enumeration_range           0.0:
1123    _list                        both
1124    _definition
1125;              Specifies distances in millimetres for the instrument geometry:
1126                 *_src/mono, the distance from the radiation source
1127                     to the monochromator,
1128                 *_mono/spec, the distance from the monochromator to
1129                     the specimen,
1130                 *_src/spec, the distance from the radiation source
1131                     to the specimen,
1132                 *_spec/anal, the distance from the specimen to the
1133                     analyser,
1134                 *_anal/detc, the distance from the analyser to the
1135                     detector,
1136                 *_spec/detc, the distance from the specimen to the
1137                     detector.
1138
1139               Note, *_src/spec is used in place of *_src/mono and *_mono/spec,
1140               if there is no monochromator in use. Also, *_spec/detc is used
1141               in place of *_spec/anal and *_anal/detc, if there is no
1142               analyser in use.
1143;
1144
1145data_pd_instr_divg_ax_
1146    loop_ _name                '_pd_instr_divg_ax_src/mono'
1147                               '_pd_instr_divg_ax_mono/spec'
1148                               '_pd_instr_divg_ax_src/spec'
1149                               '_pd_instr_divg_ax_spec/anal'
1150                               '_pd_instr_divg_ax_anal/detc'
1151                               '_pd_instr_divg_ax_spec/detc'
1152    _category                    pd_instr
1153    _type                        numb
1154    _enumeration_range           0.0:
1155    _units                       deg
1156    _units_detail               'degrees'
1157    _list                        both
1158    _definition
1159;              Describes collimation in the axial direction
1160               (perpendicular to the plane containing the incident
1161               and diffracted beams) for the instrument.
1162               Values are the maximum divergence angles in
1163               degrees, as limited by slits or other beam-line optics
1164               other than Soller slits (see _pd_instr_soller_ax_):
1165                 *_src/mono, collimation between the radiation source
1166                     and the monochromator,
1167                 *_mono/spec, collimation between the monochromator and
1168                     the specimen,
1169                 *_src/spec, collimation between the radiation source
1170                     and the specimen,
1171                 *_spec/anal, collimation between the specimen and the
1172                     analyser,
1173                 *_anal/detc, collimation between the analyser and the
1174                     detector,
1175                 *_spec/detc, collimation between the specimen and the
1176                     detector.
1177
1178               Note, *_src/spec is used in place of *_src/mono and *_mono/spec,
1179               if there is no monochromator in use and *_spec/detc is used
1180               in place of *_spec/anal and *_anal/detc, if there is no
1181               analyser in use.
1182;
1183
1184data_pd_instr_divg_eq_
1185    loop_ _name                '_pd_instr_divg_eq_src/mono'
1186                               '_pd_instr_divg_eq_mono/spec'
1187                               '_pd_instr_divg_eq_src/spec'
1188                               '_pd_instr_divg_eq_spec/anal'
1189                               '_pd_instr_divg_eq_anal/detc'
1190                               '_pd_instr_divg_eq_spec/detc'
1191    _category                    pd_instr
1192    _type                        numb
1193    _enumeration_range           0.0:
1194    _units                       deg
1195    _units_detail               'degrees'
1196    _list                        both
1197    _definition
1198;              Describes collimation in the equatorial plane (the plane
1199               containing the incident and diffracted beams) for
1200               the instrument. Values are the maximum divergence angles in
1201               degrees, as limited by slits or other beam-line optics
1202               other than Soller slits (see _pd_instr_soller_eq_):
1203                 *_src/mono, collimation between the radiation source
1204                     and the monochromator,
1205                 *_mono/spec, collimation between the monochromator and
1206                     the specimen,
1207                 *_src/spec, collimation between the radiation source
1208                     and the specimen,
1209                 *_spec/anal, collimation between the specimen and the
1210                     analyser,
1211                 *_anal/detc, collimation between the analyser and the
1212                     detector,
1213                 *_spec/detc, collimation between the specimen and the
1214                     detector.
1215
1216               Note, *_src/spec is used in place of *_src/mono and *_mono/spec,
1217               if there is no monochromator in use and *_spec/detc is used
1218               in place of *_spec/anal and *_anal/detc, if there is no
1219               analyser in use.
1220;
1221
1222data_pd_instr_geometry
1223    _name                      '_pd_instr_geometry'
1224    _category                    pd_instr
1225    _type                        char
1226    loop_ _example        Bragg-Brentano
1227                          Guinier
1228;                         Parallel beam non-focussing optics with
1229                          channel cut monochromator and linear
1230                          position-sensitive detector
1231;
1232    _definition
1233;              A description of the diffractometer type or geometry.
1234;
1235
1236data_pd_instr_location
1237    _name                      '_pd_instr_location'
1238    _category                    pd_instr
1239    _type                        char
1240    _example         'SEPD diffractometer, IPNS, Argonne National Lab (USA)'
1241    _definition
1242;              The name and location of the instrument where measurements
1243               were made. This is used primarily to identify datasets
1244               measured away from the author's home facility, at shared
1245               resources such as a reactor or spallation source.
1246;
1247
1248data_pd_instr_monochr_
1249    loop_ _name                 '_pd_instr_monochr_pre_spec'
1250                                '_pd_instr_monochr_post_spec'
1251    _category                    pd_instr
1252    _type                        char
1253    _list                        both
1254    loop_ _example              'Zr filter'   'Ge 220'   'none'
1255                                'equatorial mounted graphite (0001)'
1256                                'Si (111), antiparallel'
1257    _definition
1258;              Indicates the method used to obtain monochromatic radiation.
1259               Use _pd_instr_monochr_pre_spec to describe the primary beam
1260               monochromator (pre-specimen monochromation). Use
1261               _pd_instr_monochr_post_spec to specify the
1262               post-diffraction analyser (post-specimen) monochromation.
1263
1264               When a monochromator crystal is used, the material and the
1265               indices of the Bragg reflection are specified.
1266
1267               Note that monochromators may have either 'parallel' or
1268               'antiparallel' orientation. It is assumed that the
1269               geometry is parallel unless specified otherwise.
1270               In a parallel geometry, the position of the monochromator
1271               allows the incident beam and the final post-specimen
1272               and post-monochromator beam to be as close to parallel
1273               as possible. In a parallel geometry, the diffracting
1274               planes in the specimen and monochromator will be parallel
1275               when 2\q~monochromator~ is equal to 2\q~specimen~.
1276               For further discussion see R. Jenkins and R. Snyder,
1277               Introduction to X-ray Powder Diffraction, Wiley (1996),
1278               pp. 164-5.
1279;
1280
1281data_pd_instr_slit_ax_
1282    loop_ _name                '_pd_instr_slit_ax_src/mono'
1283                               '_pd_instr_slit_ax_mono/spec'
1284                               '_pd_instr_slit_ax_src/spec'
1285                               '_pd_instr_slit_ax_spec/anal'
1286                               '_pd_instr_slit_ax_anal/detc'
1287                               '_pd_instr_slit_ax_spec/detc'
1288    _category                    pd_instr
1289    _type                        numb
1290    _enumeration_range           0.0:
1291    _units                       mm
1292    _units_detail               'millimetres'
1293    _list                        both
1294    _definition
1295;              Describes collimation in the axial direction
1296               (perpendicular to the plane containing the incident
1297               and diffracted beams) for the instrument as a slit width
1298               (as opposed to a divergence angle).
1299               Values are the width of the slit (in millimetres) defining:
1300                 *_src/mono, collimation between the radiation source
1301                     and the monochromator,
1302                 *_mono/spec, collimation between the monochromator and
1303                     the specimen,
1304                 *_src/spec, collimation between the radiation source
1305                     and the specimen,
1306                 *_spec/anal, collimation between the specimen and the
1307                     analyser,
1308                 *_anal/detc, collimation between the analyser and the
1309                     detector,
1310                 *_spec/detc, collimation between the specimen and the
1311                     detector.
1312
1313               Note, *_src/spec is used in place of *_src/mono and *_mono/spec,
1314               if there is no monochromator in use and *_spec/detc is used
1315               in place of *_spec/anal and *_anal/detc, if there is no
1316               analyser in use.
1317;
1318
1319data_pd_instr_slit_eq_
1320    loop_ _name                '_pd_instr_slit_eq_src/mono'
1321                               '_pd_instr_slit_eq_mono/spec'
1322                               '_pd_instr_slit_eq_src/spec'
1323                               '_pd_instr_slit_eq_spec/anal'
1324                               '_pd_instr_slit_eq_anal/detc'
1325                               '_pd_instr_slit_eq_spec/detc'
1326    _category                    pd_instr
1327    _type                        numb
1328    _enumeration_range           0.0:
1329    _units                       mm
1330    _units_detail               'millimetres'
1331    _list                        both
1332    _definition
1333;              Describes collimation in the equatorial plane (the plane
1334               containing the incident and diffracted beams) for the
1335               instrument as a slit width (as opposed to a divergence angle).
1336               Values are the width of the slit (in millimetres) defining:
1337                 *_src/mono, collimation between the radiation source
1338                     and the monochromator,
1339                 *_mono/spec, collimation between the monochromator and
1340                     the specimen,
1341                 *_src/spec, collimation between the radiation source
1342                     and the specimen,
1343                 *_spec/anal, collimation between the specimen and the
1344                     analyser,
1345                 *_anal/detc, collimation between the analyser and the
1346                     detector,
1347                 *_spec/detc, collimation between the specimen and the
1348                     detector.
1349
1350               Note, *_src/spec is used in place of *_src/mono and *_mono/spec,
1351               if there is no monochromator in use and *_spec/detc is used
1352               in place of *_spec/anal and *_anal/detc, if there is no
1353               analyser in use.
1354;
1355
1356data_pd_instr_soller_ax_
1357    loop_ _name                '_pd_instr_soller_ax_src/mono'
1358                               '_pd_instr_soller_ax_mono/spec'
1359                               '_pd_instr_soller_ax_src/spec'
1360                               '_pd_instr_soller_ax_spec/anal'
1361                               '_pd_instr_soller_ax_anal/detc'
1362                               '_pd_instr_soller_ax_spec/detc'
1363    _category                    pd_instr
1364    _type                        numb
1365    _enumeration_range           0.0:
1366    _units                       deg
1367    _units_detail               'degrees'
1368    _list                        both
1369    _definition
1370;              Describes collimation in the axial direction
1371               (perpendicular to the plane containing the incident
1372               and diffracted beams) for the instrument.
1373               Values are the maximum divergence angles in
1374               degrees, as limited by Soller slits located thus:
1375                 *_src/mono, collimation between the radiation source
1376                     and the monochromator,
1377                 *_mono/spec, collimation between the monochromator and
1378                     the specimen,
1379                 *_src/spec, collimation between the radiation source
1380                     and the specimen,
1381                 *_spec/anal, collimation between the specimen and the
1382                     analyser,
1383                 *_anal/detc, collimation between the analyser and the
1384                     detector,
1385                 *_spec/detc, collimation between the specimen and the
1386                     detector.
1387
1388               Note, *_src/spec is used in place of *_src/mono and *_mono/spec,
1389               if there is no monochromator in use and *_spec/detc is used
1390               in place of *_spec/anal and *_anal/detc, if there is no
1391               analyser in use.
1392;
1393
1394data_pd_instr_soller_eq_
1395    loop_ _name                '_pd_instr_soller_eq_src/mono'
1396                               '_pd_instr_soller_eq_mono/spec'
1397                               '_pd_instr_soller_eq_src/spec'
1398                               '_pd_instr_soller_eq_spec/anal'
1399                               '_pd_instr_soller_eq_anal/detc'
1400                               '_pd_instr_soller_eq_spec/detc'
1401    _category                    pd_instr
1402    _type                        numb
1403    _enumeration_range           0.0:
1404    _units                       deg
1405    _units_detail               'degrees'
1406    _list                        both
1407    _definition
1408;              Describes collimation in the equatorial plane (the plane
1409               containing the incident and diffracted beams) for
1410               the instrument. Values are the maximum divergence angles in
1411               degrees, as limited by Soller slits located thus:
1412                 *_src/mono, collimation between the radiation source
1413                     and the monochromator,
1414                 *_mono/spec, collimation between the monochromator and
1415                     the specimen,
1416                 *_src/spec, collimation between the radiation source
1417                     and the specimen,
1418                 *_spec/anal, collimation between the specimen and the
1419                     analyser,
1420                 *_anal/detc, collimation between the analyser and the
1421                     detector,
1422                 *_spec/detc, collimation between the specimen and the
1423                     detector.
1424
1425               Note, *_src/spec is used in place of *_src/mono and *_mono/spec,
1426               if there is no monochromator in use and *_spec/detc is used
1427               in place of *_spec/anal and *_anal/detc, if there is no
1428               analyser in use.
1429;
1430
1431data_pd_instr_source_size_
1432    loop_ _name                '_pd_instr_source_size_ax'
1433                               '_pd_instr_source_size_eq'
1434    _category                    pd_instr
1435    _type                        numb
1436    _enumeration_range           0.0:
1437    _units                       mm
1438    _units_detail               'millimetres'
1439    _definition
1440;              Axial and equatorial intrinsic dimensions
1441               of the radiation source (in millimetres).
1442               The perpendicular to the plane containing the incident
1443               and scattered beam is the axial (*_ax) direction.
1444;
1445
1446data_pd_instr_special_details
1447    _name                      '_pd_instr_special_details'
1448    _category                    pd_instr
1449    _type                        char
1450    _definition
1451;              A brief description of the instrument giving
1452               details that cannot be given in other
1453               _pd_instr_ entries.
1454;
1455
1456data_pd_instr_var_illum_len
1457    _name                      '_pd_instr_var_illum_len'
1458    _category                    pd_data
1459    _list                        yes
1460    _type                        numb
1461    _enumeration_range           0.0:
1462    _units                       mm
1463    _units_detail               'millimetres'
1464    _definition
1465;              Length of the specimen that is illuminated by the radiation
1466               source (in millimetres) for instruments where
1467               the illumination length varies with 2\q (fixed
1468               divergence slits). The _pd_instr_var_illum_len
1469               values should be included in the same loop as the
1470               intensity measurements (_pd_meas_).
1471
1472               See _pd_instr_cons_illum_len for instruments where
1473               the divergence slit is \q-compensated to yield a
1474               constant illumination length.
1475;
1476
1477#............................. Processed Diffractogram
1478
1479data_pd_proc_[pd]
1480    _name                       '_pd_proc_[pd]'
1481    _category                     category_overview
1482    _type                         null
1483    _definition
1484;              This section contains the diffraction dataset after processing
1485               and application of correction terms. If the dataset is
1486               reprocessed, this section may be replaced (with addition of
1487               a new _pd_block_id entry).
1488;
1489
1490data_pd_proc_2theta_corrected
1491    _name                      '_pd_proc_2theta_corrected'
1492    _category                    pd_data
1493    _type                        numb
1494    _list                        yes
1495    _units                       deg
1496    _units_detail               'degrees'
1497    _enumeration_range           -180.0:180.0
1498    _definition
1499;              The 2\q diffraction angle in degrees of an intensity
1500               measurement where 2\q is not constant. Used if
1501               corrections such as for non-linearity, zero offset, etc.,
1502               have been applied to the _pd_meas_2theta_ values or if
1503               2\q values are computed. If the 2\q values
1504               are evenly spaced, _pd_proc_2theta_range_min,
1505               _pd_proc_2theta_range_max and _pd_proc_2theta_range_inc
1506               may be used to specify the 2\q values.
1507;
1508
1509data_pd_proc_2theta_range_
1510    loop_ _name                '_pd_proc_2theta_range_min'
1511                               '_pd_proc_2theta_range_max'
1512                               '_pd_proc_2theta_range_inc'
1513    _category                    pd_proc_info
1514    _type                        numb
1515    _units                       deg
1516    _units_detail               'degrees'
1517    _enumeration_range           -180.0:180.0
1518    _definition
1519;              The range of 2\q diffraction angles in degrees for the
1520               measurement of intensities. These may be used in place of the
1521               _pd_proc_2theta_corrected values; or in the case of white-beam
1522               experiments it will define the fixed 2\q value.
1523;
1524
1525data_pd_proc_d_spacing
1526    _name                      '_pd_proc_d_spacing'
1527    _category                    pd_data
1528    _type                        numb
1529    _list                        yes
1530    _enumeration_range           0.0:
1531    _units                       A
1532    _units_detail               'angstroms'
1533    _definition
1534;              d-spacing corresponding to an intensity point
1535               from Bragg's law, d = \l/(2 sin\q) in units of angstroms.
1536;
1537
1538data_pd_proc_energy_
1539    loop_ _name                '_pd_proc_energy_incident'
1540                               '_pd_proc_energy_detection'
1541    _category                    pd_data
1542    _type                        numb
1543    _list                        both
1544    _units                       eV
1545    _units_detail               'electron volts'
1546    _enumeration_range           0.0:
1547    _definition
1548;              Incident energy in electron-volts of the source computed
1549               from secondary calibration information (time-of-flight
1550               and synchrotron).
1551               Detection energy in electron-volts selected by the analyser,
1552               if not the same as the incident energy (triple-axis or energy
1553               dispersive data). This may be a single value or may vary for
1554               each data point (triple-axis and time-of-flight data).
1555;
1556
1557data_pd_proc_info_author_address
1558    _name                      '_pd_proc_info_author_address'
1559    _category                    pd_proc_info
1560    _type                        char
1561    _list                        both
1562    _list_reference            '_pd_proc_info_author_name'
1563    _definition
1564;               The address of the person who processed the data.
1565                If there is more than one person this will be looped with
1566                _pd_proc_info_author_name.
1567;
1568
1569data_pd_proc_info_author_email
1570    _name                      '_pd_proc_info_author_email'
1571    _category                    pd_proc_info
1572    _type                        char
1573    _list                        both
1574    _list_reference            '_pd_proc_info_author_name'
1575    _definition
1576;               The email address of the person who processed the
1577                data.  If there is more than one person this will be looped
1578                with _pd_proc_info_author_name.
1579;
1580
1581data_pd_proc_info_author_fax
1582    _name                      '_pd_proc_info_author_fax'
1583    _category                    pd_proc_info
1584    _type                        char
1585    _list                        both
1586    _list_reference            '_pd_proc_info_author_name'
1587    _definition
1588;               The fax number of the person who processed the data.
1589                If there is more than one person this will be looped with
1590                _pd_proc_info_author_name. The recommended style includes
1591                the international dialing prefix, the area code in
1592                parentheses, followed by the local number with no spaces.
1593;
1594
1595data_pd_proc_info_author_name
1596    _name                      '_pd_proc_info_author_name'
1597    _category                    pd_proc_info
1598    _type                        char
1599    _list                        both
1600    _definition
1601;               The name of the person who processed the data, if different
1602                from the person(s) who measured the dataset. The family
1603                name(s), followed by a comma and including any dynastic
1604                components, precedes the first name(s) or initial(s). For
1605                more than one person use a loop to specify multiple values.
1606;
1607
1608data_pd_proc_info_author_phone
1609    _name                      '_pd_proc_info_author_phone'
1610    _category                    pd_proc_info
1611    _type                        char
1612    _list                        both
1613    _list_reference            '_pd_proc_info_author_name'
1614    _definition
1615;               The telephone number of the person who processed the data.
1616                If there is more than one person this will be looped
1617                with _pd_proc_info_author_name. The recommended style includes
1618                the international dialing prefix, the area code in
1619                parentheses, followed by the local number with no spaces.
1620;
1621
1622data_pd_proc_info_data_reduction
1623    _name                      '_pd_proc_info_data_reduction'
1624    _category                    pd_proc_info
1625    _type                        char
1626    _definition
1627;              Description of processing steps applied in the data reduction
1628               process (background subtraction, \a-2 stripping, smoothing,
1629               etc.). Include details of the program(s) used, etc.
1630;
1631
1632data_pd_proc_info_datetime
1633    _name                      '_pd_proc_info_datetime'
1634    _category                    pd_proc_info
1635    _type                        char
1636    _list                        both
1637    _example                     1990-07-13T14:40
1638    _definition
1639;              Date(s) and time(s) when the dataset was processed.
1640               May be looped if multiple processing steps were used.
1641
1642               Dates and times should be specified in the standard CIF
1643               format 'yyyy-mm-ddThh:mm:ss+zz'. Use of seconds and a
1644               time zone is optional, but use of hours and minutes is
1645               strongly encouraged.
1646;
1647
1648data_pd_proc_info_excluded_regions
1649    _name                      '_pd_proc_info_excluded_regions'
1650    _category                    pd_proc_info
1651    _type                        char
1652    _example                    '20 to 21 degrees unreliable due to beam dump'
1653    _definition
1654;              Description of regions in the diffractogram excluded
1655               from processing along with a justification of why the
1656               datapoints were not used.
1657;
1658
1659data_pd_proc_info_special_details
1660    _name                      '_pd_proc_info_special_details'
1661    _category                    pd_proc_info
1662    _type                        char
1663    _definition
1664;              Detailed description of any non-routine processing steps
1665               applied due to any irregularities in this particular dataset.
1666;
1667
1668data_pd_proc_intensity_
1669    loop_ _name                '_pd_proc_intensity_net'
1670                               '_pd_proc_intensity_total'
1671                               '_pd_proc_intensity_bkg_calc'
1672                               '_pd_proc_intensity_bkg_fix'
1673                               '_pd_proc_intensity_incident'
1674                               '_pd_proc_intensity_norm'
1675    _category                    pd_data
1676    _type                        numb
1677    _type_conditions             esd
1678    _list                        yes
1679    _enumeration_range           0.0:
1680    _definition
1681;              _pd_proc_intensity_net contains intensity values for the
1682               processed diffractogram for each data point (see
1683               _pd_proc_2theta_, _pd_proc_wavelength, etc.) after
1684               correction and normalisation factors have been applied
1685               (in contrast to _pd_meas_counts_ values which are
1686               uncorrected).
1687
1688               _pd_proc_intensity_total contains intensity values for the
1689               processed diffractogram for each data point where
1690               background, normalisation and other corrections have not
1691               been applied.
1692
1693               Inclusion of s.u.'s for these values is strongly recommended.
1694
1695               _pd_proc_intensity_bkg_calc is intended to contain the
1696               background intensity for every data point where the
1697               background function has been fit or estimated (for example in
1698               all Rietveld and profile fits).
1699
1700               If the background is estimated for a limited number of points
1701               and the calculated background is then extrapolated from
1702               these fixed points, indicate the background values for
1703               these points with _pd_proc_intensity_bkg_fix. Use a value
1704               of '.' for data points where a fixed background has not
1705               been defined. The extrapolated background at every point
1706               may be specified using _pd_proc_intensity_bkg_calc.
1707
1708               Background values should be on the same scale as the
1709               _pd_proc_intensity_net values. Thus normalisation and
1710               correction factors should be applied before
1711               background subtraction (or should be applied to the
1712               background values equally).
1713
1714               If the intensities have been corrected for a variation of the
1715               incident intensity as a function of a data collection
1716               variable (examples: source fluctuations in synchrotrons,
1717               \q-compensated slits in conventional diffractometers,
1718               spectral corrections for white-beam experiments) the
1719               correction function should be specified as
1720               _pd_proc_intensity_incident. The normalisation should be
1721               specified in _pd_proc_intensity_incident as a value to be
1722               used to divide the measured intensities to obtained the
1723               normalised diffractogram. Thus, the
1724               _pd_proc_intensity_incident values should increase as the
1725               incident flux is increased.
1726
1727               The other normalisation factors applied to the dataset (for
1728               example, Lp corrections, compensation for variation in
1729               counting time) may be specified in _pd_proc_intensity_norm.
1730               The function should be specified as the one used to divide the
1731               measured intensities.
1732;
1733
1734data_pd_proc_number_of_points
1735    _name                      '_pd_proc_number_of_points'
1736    _category                    pd_proc_info
1737    _type                        numb
1738    _enumeration_range           1:
1739    _definition
1740;              The total number of data points in the processed diffractogram.
1741;
1742
1743data_pd_proc_recip_len_Q
1744    _name                      '_pd_proc_recip_len_Q'
1745    _category                    pd_data
1746    _type                        numb
1747    _list                        yes
1748    _enumeration_range           0.0:
1749    _units                       A^-1^
1750    _units_detail               'reciprocal angstroms'
1751    _definition
1752;              Length in reciprocal space (|Q|= 2\p/d) corresponding to
1753               an intensity point. Units are inverse angstroms.
1754;
1755
1756data_pd_proc_wavelength
1757    _name                      '_pd_proc_wavelength'
1758    _category                    pd_data
1759    _type                        numb
1760    _list                        both
1761    _enumeration_range           0.0:
1762    _units                       A
1763    _units_detail               'Angstroms'
1764    _definition
1765;              Wavelength in angstroms for the incident radiation as
1766               computed from secondary calibration information. This will
1767               be most appropriate for time-of-flight and synchrotron
1768               measurements. This will be a single value for
1769               continuous-wavelength methods or may vary for each data point
1770               and be looped with the intensity values for energy-dispersive
1771               measurements.
1772;
1773
1774#......................... Least-squares (Profile/Rietveld fit) parameters
1775
1776data_pd_proc_ls_[pd]
1777    _name                       '_pd_proc_ls_[pd]'
1778    _category                     category_overview
1779    _type                         null
1780
1781    _definition
1782;              This section is used to define parameters relevant to a
1783               least-squares fit to a powder diffractogram, using a Rietveld
1784               or other full-profile (e.g. Pawley or Le Bail methods) fit.
1785
1786               Note that values in this section refer to full-pattern fitting.
1787               Use the appropriate items for single-crystal analyses from the
1788               core dictionary for structural refinements using diffraction
1789               intensities estimated from a powder diffractogram by pattern
1790               decomposition methods. Also note that many entries in the
1791               core _refine_ls_ entries may also be useful (for example
1792               _refine_ls_shift/esd_).
1793;
1794
1795data_pd_proc_ls_background_function
1796    _name                      '_pd_proc_ls_background_function'
1797    _category                    pd_proc_ls
1798    _type                        char
1799    _definition
1800;              Description of the background treatment mechanism used to
1801               fit the dataset.
1802
1803               For refinements where background is computed from a
1804               function fit to the difference between obs and calc, it is
1805               recommended that in addition to a description of the
1806               function (e.g. Chebychev polynomial), the actual equation(s)
1807               used be included in TeX, or a programming language such
1808               as FORTRAN or C. Include also the values used for the
1809               coefficients used in the background function with their
1810               s.u.'s. The background values for each data point
1811               computed from the function should be specified in
1812               _pd_proc_intensity_bkg_calc.
1813
1814               If background correction is performed using extrapolation
1815               from a set of points at fixed locations, these points
1816               should be defined using _pd_proc_intensity_bkg_fix, and
1817               _pd_proc_ls_background_function should indicate the
1818               extrapolation method (linear extrapolation, spline, etc.).
1819               _pd_proc_ls_background_function should also indicate how the
1820               points were determined (automatically, by visual estimation,
1821               etc.) and whether the values were refined to improve the
1822               agreement. The extrapolated background intensity value for
1823               each data point should be specified in
1824               _pd_proc_intensity_bkg_calc.
1825;
1826
1827data_pd_proc_ls_peak_cutoff
1828    _name                      '_pd_proc_ls_peak_cutoff'
1829    _category                    pd_proc_ls
1830    _type                        numb
1831    _list                        no
1832    _definition
1833;              Describes where peak intensity computation is
1834               discontinued as a fraction of the intensity of the
1835               peak at maximum. Thus for a value of 0.005, the
1836               tails of a diffraction peak are neglected
1837               after the intensity has dropped below 0.5% of the
1838               diffraction intensity at the maximum.
1839;
1840
1841data_pd_proc_ls_pref_orient_corr
1842    _name                      '_pd_proc_ls_pref_orient_corr'
1843    _category                    pd_proc_ls
1844    _type                        char
1845    _definition
1846;              Description of the preferred orientation correction if
1847               such a correction is used. Omitting this entry
1848               implies no preferred orientation correction
1849               has been used. If a function form is used, it is
1850               recommended that the actual equation in TeX, or a
1851               programming language, be used to specify the function as
1852               well as a description. Include the value(s) used for the
1853               correction with s.u.'s.
1854;
1855
1856data_pd_proc_ls_prof_
1857    loop_ _name                 '_pd_proc_ls_prof_R_factor'
1858                                '_pd_proc_ls_prof_wR_factor'
1859                                '_pd_proc_ls_prof_wR_expected'
1860    _category                    pd_proc_ls
1861    _type                        numb
1862    _enumeration_range           0.0:
1863    _definition
1864;              Rietveld/Profile fit R factors.
1865
1866               Note that the R factor computed for Rietveld refinements
1867               using the extracted reflection intensity values (often
1868               called the Rietveld or Bragg R factor, R~B~) is not properly
1869               a profile R factor. This R factor may be specified using
1870               _refine_ls_R_I_factor. (Some authors report
1871               _refine_ls_R_Fsqd_factor or _refine_ls_R_factor_all
1872               as the Rietveld or Bragg R factor. While it is appropriate
1873               to compute and report any or all of these R factors,
1874               the names "Rietveld or Bragg R factor" refer strictly to
1875               _refine_ls_R_I_factor.)
1876
1877              _pd_proc_ls_prof_R_factor, often called R~p~, is an
1878                unweighted fitness metric for the agreement between the
1879                observed and computed diffraction patterns
1880                   R~p~ = sum~i~ | I~obs~(i) - I~calc~(i) |
1881                          / sum~i~ ( I~obs~(i) )
1882              _pd_proc_ls_prof_wR_factor, often called R~wp~, is a
1883                weighted fitness metric for the agreement between the
1884                observed and computed diffraction patterns
1885                  R~wp~ = SQRT {
1886                           sum~i~ ( w(i) [ I~obs~(i) - I~calc~(i) ]^2^ )
1887                           / sum~i~ ( w(i) [I~obs~(i)]^2^ ) }
1888
1889              _pd_proc_ls_prof_wR_expected, sometimes called the
1890                theoretical R~wp~ or R~exp~, is a weighted fitness metric for
1891                the statistical precision of the dataset. For an idealised fit,
1892                where all deviations between the observed intensities and
1893                those computed from the model are due to statistical
1894                fluctuations, the observed R~wp~ should match the expected
1895                R factor. In reality R~wp~ will always be higher than
1896                R~exp~.
1897                  R~exp~ = SQRT {
1898                                 (n - p)  / sum~i~ ( w(i) [I~obs~(i)]^2^ ) }
1899
1900                Note that in the above equations,
1901                   w(i) is the weight for the ith data point (see
1902                        _pd_proc_ls_weight).
1903                   I~obs~(i) is the observed intensity for the ith data
1904                        point, sometimes referred to as y~i~(obs) or
1905                        y~oi~. (See _pd_meas_counts_total,
1906                        _pd_meas_intensity_total or _pd_proc_intensity_total.)
1907                   I~calc~(i) is the computed intensity for the ith data
1908                        point with background and other corrections
1909                        applied to match the scale of the observed dataset,
1910                        sometimes referred to as y~i~(calc) or
1911                        y~ci~. (See _pd_calc_intensity_total.)
1912                   n is the total number of data points (see
1913                        _pd_proc_number_of_points) less the number of
1914                        data points excluded from the refinement.
1915                   p is the total number of refined parameters.
1916;
1917
1918data_pd_proc_ls_profile_function
1919    _name                      '_pd_proc_ls_profile_function'
1920    _category                    pd_proc_ls
1921    _type                        char
1922    _definition
1923;              Description of the profile function used to
1924               fit the dataset. If a function form is used, it is
1925               recommended that the actual equation in TeX, or a
1926               programming language, be used to specify the function as
1927               well as a description. Include the values used for the
1928               profile function coefficients and their s.u.'s.
1929;
1930
1931data_pd_proc_ls_special_details
1932    _name                      '_pd_proc_ls_special_details'
1933    _category                    pd_proc_ls
1934    _type                        char
1935    _definition
1936;              Additional characterisation information relevant to
1937               non-routine steps used for refinement of a structural model
1938               that cannot be specified elsewhere.
1939;
1940
1941data_pd_proc_ls_weight
1942    _name                      '_pd_proc_ls_weight'
1943    _category                    pd_data
1944    _type                        numb
1945    _list                        yes
1946    _enumeration_range           0:
1947    _definition
1948;              Weight applied to each profile point. These values
1949               may be omitted if the weights are 1/u^2^ where
1950               u is the s.u. for the _pd_proc_intensity_net values.
1951
1952               A weight value of zero is used to indicate a data
1953               point not used for refinement (see
1954               _pd_proc_info_excluded_regions).
1955;
1956
1957#............................. Calculated Diffractogram
1958
1959data_pd_calc_[pd]
1960    _name                       '_pd_calc_[pd]'
1961    _category                     category_overview
1962    _type                         null
1963
1964    _definition
1965;              This section is used for storing a computed diffractogram trace.
1966               This may be a simulated powder pattern for a material from a
1967               program such as LAZY/PULVERIX or the computed intensities from a
1968               Rietveld refinement.
1969;
1970
1971
1972data_pd_calc_intensity_
1973    loop_ _name                 '_pd_calc_intensity_net'
1974                                '_pd_calc_intensity_total'
1975    _category                    pd_data
1976    _type                        numb
1977    _list                        yes
1978    _enumeration_range           0.0:
1979    _definition
1980;              Intensity values for a computed diffractogram at
1981               each angle setting. Values should be computed at the
1982               same locations as the processed diffractogram, and thus
1983               the numbers of points will be defined by
1984               _pd_proc_number_of_points and point positions may
1985               be defined using _pd_proc_2theta_range_ or
1986               _pd_proc_2theta_corrected.
1987
1988               Use _pd_calc_intensity_net if the computed diffractogram
1989               does not contain background or normalisation corrections
1990               and thus is specified on the same scale as the
1991               _pd_proc_intensity_net.
1992
1993               Use _pd_calc_intensity_total if the computed diffraction
1994               pattern includes background or normalisation corrections
1995               (or both) and thus is specified on the same scale as the
1996               observed intensities (_pd_meas_counts_ or _pd_meas_intensity_).
1997
1998               If an observed pattern is included, _pd_calc_intensity_
1999               should be looped with either _pd_proc_intensity_net,
2000               _pd_meas_counts_ or _pd_meas_intensity_.
2001;
2002
2003data_pd_calc_method
2004    _name                      '_pd_calc_method'
2005    _category                    pd_calc
2006    _type                        char
2007    _definition
2008;              A description of the method used for calculation of
2009               the intensities in _pd_calc_intensity_. If the pattern was
2010               calculated from crystal structure data, the atom coordinates
2011               and other crystallographic information should be included
2012               using the core CIF _atom_site_ and _cell_ data items.
2013;
2014
2015
2016#......................... Peak Table
2017
2018data_pd_peak_[pd]
2019    _name                       '_pd_peak_[pd]'
2020    _category                     category_overview
2021    _type                         null
2022    _definition
2023;              This section contains peak information extracted from the
2024               measured or, if present, the processed diffractogram. Each
2025               peak in this table will have a unique label (see _pd_peak_id).
2026               The reflections and phases associated with each peak will be
2027               specified in a later section (see the _pd_refln_ and
2028               _pd_phase_ sections).
2029
2030               Note that peak positions are customarily determined from the
2031               processed diffractogram and thus corrections for position
2032               and intensity will have been previously applied.
2033;
2034
2035data_pd_peak_2theta_
2036    loop_ _name                  '_pd_peak_2theta_centroid'
2037                                 '_pd_peak_2theta_maximum'
2038    _category                    pd_peak
2039    _type                        numb
2040    _type_conditions             esd
2041    _list                        yes
2042    _list_reference            '_pd_peak_id'
2043    _units                       deg
2044    _units_detail               'degrees'
2045    _enumeration_range           0.0:180.0
2046    _definition
2047;              Position of the centroid and maximum of a peak as a
2048               2\q angle in degrees.
2049;
2050
2051data_pd_peak_d_spacing
2052    _name                      '_pd_peak_d_spacing'
2053    _category                    pd_peak
2054    _type                        numb
2055    _type_conditions             esd
2056    _list                        yes
2057    _list_reference            '_pd_peak_id'
2058    _enumeration_range           0.0:
2059    _units                       A
2060    _units_detail               'angstroms'
2061    _definition
2062;              Peak position as a d-spacing in angstroms.
2063;
2064
2065data_pd_peak_id
2066    _name                      '_pd_peak_id'
2067    _category                    pd_peak
2068    _type                        char
2069    _list                        yes
2070    _list_mandatory              yes
2071    _list_uniqueness           '_pd_peak_id'
2072    _list_link_child           '_pd_refln_peak_id'
2073    _definition
2074;              An arbitrary code is assigned to each peak. Used to link with
2075               _pd_refln_peak_id so that multiple hkl and/or phase
2076               identifications can be assigned to a single peak.
2077               Each peak will have a unique code. In cases
2078               where two peaks are severely overlapped, it may be
2079               desirable to list them as a single peak.
2080
2081               A peak id must be included for every peak.
2082;
2083
2084data_pd_peak_intensity
2085    _name                      '_pd_peak_intensity'
2086    _category                    pd_peak
2087    _type                        numb
2088    _type_conditions             esd
2089    _list                        yes
2090    _list_reference            '_pd_peak_id'
2091    _enumeration_range           0.0:
2092    _definition
2093;              Integrated area for the peak, with the same scaling as
2094               the _pd_proc_intensity_ values. Good practice is to
2095               include s.u.'s for these values.
2096;
2097
2098data_pd_peak_pk_height
2099    _name                      '_pd_peak_pk_height'
2100    _category                    pd_peak
2101    _type                        numb
2102    _type_conditions             esd
2103    _list                        yes
2104    _list_reference            '_pd_peak_id'
2105    _enumeration_range           0.0:
2106    _definition
2107;              The maximum intensity of the peak, either extrapolated,
2108               or the highest observed intensity value. The same
2109               scaling is used for the _pd_proc_intensity_ values.
2110               Good practice is to include s.u.'s for these values.
2111;
2112
2113data_pd_peak_special_details
2114    _name                      '_pd_peak_special_details'
2115    _category                    pd_peak_method
2116    _type                        char
2117    _definition
2118;              Detailed description of any non-routine processing steps
2119               used for peak determination or other comments
2120               related to the peak table that cannot be described elsewhere.
2121;
2122
2123data_pd_peak_wavelength_id
2124    _name                      '_pd_peak_wavelength_id'
2125    _category                    pd_peak
2126    _type                        char
2127    _list                        yes
2128    _list_reference            '_pd_peak_id'
2129    _list_link_parent          '_diffrn_radiation_wavelength_id'
2130    _definition
2131;              Code identifying the wavelength appropriate for this peak
2132               from the wavelengths in the _diffrn_radiation_ list.
2133               (See _diffrn_radiation_wavelength_id.) Most commonly used
2134               to distinguish K\a~1~ peaks from K\a~2~ or designate
2135               where K\a~1~ and K\a~2~ peaks cannot be resolved. For
2136               complex peak tables, with multiple superimposed peaks,
2137               specify wavelengths in the reflection table using
2138               _pd_refln_wavelength_id rather than identifying peaks by
2139               wavelength.
2140;
2141
2142data_pd_peak_width_2theta
2143    _name                      '_pd_peak_width_2theta'
2144    _category                    pd_peak
2145    _type                        numb
2146    _type_conditions             esd
2147    _list                        yes
2148    _list_reference            '_pd_peak_id'
2149    _enumeration_range           0.0:180.0
2150    _units                       deg
2151    _units_detail                degrees
2152    _definition
2153;              Peak width as full-width at half-maximum expressed as
2154               2\q value in degrees.
2155;
2156
2157data_pd_peak_width_d_spacing
2158    _name                      '_pd_peak_width_d_spacing'
2159    _category                    pd_peak
2160    _type                        numb
2161    _type_conditions             esd
2162    _list                        yes
2163    _list_reference            '_pd_peak_id'
2164    _enumeration_range           0.0:
2165    _units                       A
2166    _units_detail               'angstroms'
2167    _definition
2168;              Peak width as full-width at half-maximum expressed as
2169               a d-spacing in angstroms.
2170;
2171
2172#............................ Crystalline Phase Assignments
2173
2174data_pd_phase_[pd]
2175    _name                       '_pd_phase_[pd]'
2176    _category                     category_overview
2177    _type                         null
2178
2179    _definition
2180;              This section contains a description of the crystalline phases
2181               present in the powder diffraction dataset. Note that if
2182               multiple-phase Rietveld or other structural analysis is
2183               performed, the structural results will be placed in different
2184               data blocks, using CIF entries from the core CIF dictionary.
2185
2186               The _pd_phase_block_id entry points to the CIF block with
2187               structural parameters for each crystalline phase. The
2188               _pd_phase_id serves to link to _pd_refln_phase_id which is
2189               used to label peaks by phase.
2190;
2191
2192data_pd_phase_block_id
2193    _name                      '_pd_phase_block_id'
2194    _category                    pd_phase
2195    _type                        char
2196    _list                        yes
2197    _list_reference            '_pd_phase_id'
2198    _definition
2199;              A block id code identifying the phase contributing to
2200               the diffraction peak. The data block containing the
2201               crystallographic information for this phase will be
2202               identified with a _pd_block_id code matching the
2203               code in _pd_phase_block_id.
2204;
2205
2206data_pd_phase_id
2207    _name                      '_pd_phase_id'
2208    _category                    pd_phase
2209    _type                        char
2210    _list                        yes
2211    _list_mandatory              yes
2212    _list_link_child           '_pd_refln_phase_id'
2213    _list_uniqueness           '_pd_phase_id'
2214    _definition
2215;              A code for each crystal phase used to link with
2216               _pd_refln_phase_id.
2217;
2218
2219data_pd_phase_mass_%
2220    _name                      '_pd_phase_mass_%'
2221    _category                    pd_phase
2222    _type                        numb
2223    _type_conditions             esd
2224    _list                        yes
2225    _list_reference            '_pd_phase_id'
2226    _enumeration_range           0.0:100.0
2227    _definition
2228;              Percent composition of the specified crystal phase
2229               expressed as the total mass of the component
2230               with respect to the total mass of the specimen.
2231;
2232
2233data_pd_phase_name
2234    _name                      '_pd_phase_name'
2235    _category                    pd_phase
2236    _type                        char
2237    _list                        both
2238    _list_reference            '_pd_phase_id'
2239    _definition
2240;              The name of the crystal phase identified by _pd_phase_id.
2241               It may be designated as unknown or by a structure type, etc.
2242;
2243
2244#............................ Peak Reflection Identification
2245
2246data_pd_refln_[pd]
2247    _name                       '_pd_refln_[pd]'
2248    _category                     category_overview
2249    _type                         null
2250    _definition
2251;              This section provides a mechanism to identify each peak in the
2252               peak-table section (_pd_peak_) with the phase(s) (_pd_phase_id)
2253               and the reflection indices (_refln_index_) associated with the
2254               peak.  There are no restrictions on the number of phases or
2255               reflections associated with an observed peak. Reflections may
2256               also be included that are not observed; use '.' for the
2257               _pd_refln_peak_id.
2258;
2259
2260data_pd_refln_peak_id
2261    _name                      '_pd_refln_peak_id'
2262    _category                    refln
2263    _type                        char
2264    _list                        yes
2265    loop_ _list_reference      '_refln_index_h'
2266                               '_refln_index_k'
2267                               '_refln_index_l'
2268    _list_link_parent          '_pd_peak_id'
2269    _definition
2270;              Code which identifies the powder diffraction peak that
2271               contains the current reflection. This code must match a
2272               _pd_peak_id code.
2273;
2274
2275data_pd_refln_phase_id
2276    _name                      '_pd_refln_phase_id'
2277    _category                    refln
2278    _type                        char
2279    _list                        yes
2280    loop_ _list_reference      '_refln_index_h'
2281                               '_refln_index_k'
2282                               '_refln_index_l'
2283    _list_link_parent          '_pd_phase_id'
2284    _definition
2285;              Code which identifies the crystal phase associated with this
2286               reflection. This code must match a _pd_phase_id code.
2287;
2288
2289data_pd_refln_wavelength_id
2290    _name                      '_pd_refln_wavelength_id'
2291    _category                    refln
2292    _type                        char
2293    _list                        yes
2294    loop_ _list_reference      '_refln_index_h'
2295                               '_refln_index_k'
2296                               '_refln_index_l'
2297    _list_link_parent          '_diffrn_radiation_wavelength_id'
2298    _definition
2299;              Code which identifies the wavelength associated with the
2300               reflection and the peak pointed to by _pd_refln_peak_id.
2301               This code must match a _diffrn_radiation_wavelength_id code.
2302;
2303
2304#............................. Sample Preparation Information
2305
2306data_pd_prep_[pd]
2307    _name                       '_pd_prep_[pd]'
2308    _category                     category_overview
2309    _type                         null
2310    _definition
2311;              This section contains descriptive information on how the
2312               sample is prepared.
2313;
2314
2315data_pd_prep_conditions
2316    _name                      '_pd_prep_conditions'
2317    _category                    pd_prep
2318    _type                        char
2319    _definition
2320;              A description of how the material was prepared
2321               (reaction conditions, etc.)
2322;
2323
2324data_pd_prep_cool_rate
2325    _name                      '_pd_prep_cool_rate'
2326    _category                    pd_prep
2327    _type                        numb
2328    _type_conditions             esd
2329    _enumeration_range           0.0:
2330    _units                       Kmin^-1^
2331    _units_detail               'kelvins/minute'
2332    _definition
2333;              Cooling rate in kelvins per minute for samples prepared
2334               at high temperatures. If the cooling rate is not linear
2335               or is unknown (e.g. quenched samples), it should be
2336               described instead in _pd_prep_conditions.
2337;
2338
2339data_pd_prep_pressure
2340    _name                      '_pd_prep_pressure'
2341    _category                    pd_prep
2342    _type                        numb
2343    _type_conditions             esd
2344    _enumeration_range           0.0:
2345    _units                       kPa
2346    _units_detail               'kilopascals'
2347    _definition
2348;              Preparation pressure of the sample in kilopascals. This
2349               is particularly important for materials which are metastable
2350               at the measurement pressure, _diffrn_ambient_pressure.
2351;
2352
2353data_pd_prep_temperature
2354    _name                      '_pd_prep_temperature'
2355    _category                    pd_prep
2356    _type                        numb
2357    _type_conditions             esd
2358    _enumeration_range           0.0:
2359    _units                       K
2360    _units_detail               'kelvin'
2361    _definition
2362;              Preparation temperature in kelvins of the sample. This is
2363               particularly important for materials which are metastable
2364               at the measurement temperature, _diffrn_ambient_temperature.
2365;
2366
2367#............................. Characterisation Information
2368
2369data_pd_char_[pd]
2370    _name                       '_pd_char_[pd]'
2371    _category                     category_overview
2372    _type                         null
2373    _definition
2374;   This section contains experimental (non-diffraction) information
2375    relevant to the chemical and physical nature of the material.
2376;
2377
2378data_pd_char_atten_coef_mu_
2379    loop_ _name                '_pd_char_atten_coef_mu_obs'
2380                               '_pd_char_atten_coef_mu_calc'
2381    _category                    pd_char
2382    _type                        numb
2383    _enumeration_range           0.0:
2384    _units                       mm^-1^
2385    _units_detail                'reciprocal millimetres'
2386    _definition
2387;              The observed and calculated linear attenuation coefficient,
2388               \m in units of inverse millimetres. Note that this quantity
2389               is sometimes referred to as the mass absorption coefficient;
2390               however, this term accounts for other potentially significant
2391               losses of incident radiation, for example incoherent
2392               scattering of neutrons.
2393
2394               The calculated \m will be obtained from the atomic content of
2395               the cell, the average density (allowing for specimen packing)
2396               and the radiation wavelength. The observed \m will be
2397               determined by a transmission measurement.
2398               Note that _pd_char_atten_coef_mu_calc will differ from
2399               _exptl_absorpt_coefficient_mu if the packing density is
2400               not unity.
2401;
2402
2403data_pd_char_colour
2404    _name                      '_pd_char_colour'
2405    _category                    pd_char
2406    _type                        char
2407    loop_ _example               dark_green
2408                                 orange_red
2409                                 brownish_red
2410                                 yellow_metallic
2411    _definition
2412;              The colour of the material used for the measurement.
2413               To facilitate more standardised use of names, the
2414               following guidelines for colour naming developed by
2415               Peter Bayliss for the ICDD should be used. Note that
2416               combinations of descriptors are separated by an
2417               underscore.
2418
2419               Allowed colours are:
2420                 colourless, white, black, gray, brown, red, pink,
2421                 orange, yellow, green, blue, violet.
2422
2423               Colours may be modified using prefixes of:
2424                 light, dark, whitish, blackish, grayish, brownish,
2425                 reddish, pinkish, orangish, yellowish, greenish, bluish.
2426
2427               Intermediate hues may be indicated with two colours:
2428               e.g. blue_green or bluish_green.
2429
2430               For metallic materials, the term metallic may be added:
2431               e.g. reddish_orange_metallic for copper.
2432
2433               The ICDD standard allows commas to be used for minerals
2434               that occur with ranges of colours; however this usage is
2435               not appropriate for description of a single sample.
2436;
2437
2438data_pd_char_particle_morphology
2439    _name                      '_pd_char_particle_morphology'
2440    _category                    pd_char
2441    _type                        char
2442    _definition
2443;              A description of the sample morphology and estimates for
2444               particle sizes (before grinding/sieving, if noted by
2445               _pd_spec_preparation). Include the method used for
2446               these estimates (SEM, visual estimate...).
2447;
2448
2449data_pd_char_special_details
2450    _name                      '_pd_char_special_details'
2451    _category                    pd_char
2452    _type                        char
2453    _definition
2454;              Additional characterisation information relevant to the sample
2455               or documentation of non-routine processing steps used
2456               for characterisation.
2457;
2458
2459#............................. Data Tabulation and Book-keeping Across Tables
2460
2461data_pd_data_[pd]
2462    _name                       '_pd_data_[pd]'
2463    _category                     category_overview
2464    _type                         null
2465    loop_ _example
2466          _example_detail
2467# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
2468;
2469    loop_
2470      _pd_meas_intensity_total
2471      _pd_proc_ls_weight
2472      _pd_proc_intensity_bkg_calc
2473      _pd_calc_intensity_total
2474    240(15)       0.00417     214.5   214.5
2475    219(15)       0.00457     214.3   214.2
2476    206(14)       0.00485     214.0   214.0
2477    212(15)       0.00472     213.8   213.7
2478    190(14)       0.00526     213.5   213.5
2479    203(14)       0.00493     213.2   213.2
2480     # - - - - data truncated for brevity - - - -
2481;
2482;   Example 1 - data set collected for a two-phase sample (Al~2~O~3~/Si)
2483                by B. H. Toby, '1997-01-29T16:37|POWSET_01|B.Toby|..NIST-D5000'
2484;
2485# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
2486;
2487     loop_
2488      _pd_meas_point_id
2489      _pd_meas_intensity_total
2490    1  240(15) 2  219(15) 3  206(14) 4  212(15) 5  190(14) 6  203(14)
2491
2492     loop_
2493      _pd_proc_point_id
2494      _pd_proc_ls_weight
2495      _pd_proc_intensity_bkg_calc
2496    1  0.00417  214.5      2  0.00457  214.3
2497    3  0.00485  214.0      4  0.00472  213.8
2498    5  0.00526  213.5      6  0.00493  213.2
2499
2500     loop_
2501      _pd_calc_point_id
2502      _pd_calc_intensity_total
2503    1   214.5 2   214.2 3   214.0 4   213.7 5   213.5 6   213.2
2504
2505;
2506;   Example 2 - the data of Example 1 split into three separate tables.
2507;
2508# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
2509;
2510   loop_
2511     _pd_meas_point_id
2512     _pd_meas_2theta_scan
2513     _pd_meas_intensity_total
2514            1  21.0   24
2515            2  21.2   32
2516            3  21.4   67
2517            4  21.6   98
2518
2519   loop_
2520     _pd_calc_point_id
2521     _pd_calc_2theta_scan
2522     _pd_calc_intensity_total
2523            1   21.0  26
2524            1a  21.3  56
2525            4   21.6  76
2526            4a  21.9  90
2527
2528;
2529;   Example 3 - hypothetical example where the measured and calculated
2530                points are not in one-to-one correspondence.
2531;
2532# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
2533    _definition
2534;              The PD_DATA category contains raw, processed and calculated
2535               data points in a diffraction dataset. In many cases, it is
2536               convenient to tabulate calculated values against the
2537               raw and processed measurements, and so the various
2538               _pd_meas_, _pd_proc_ and _pd_calc_ data items belonging
2539               to this category may be looped together. In some instances,
2540               however, it makes more sense to maintain separate tables of
2541               the data contributing to the measured and processed
2542               diffractograms (for example a profile may be calculated
2543               at two-theta values different from those of the measured
2544               data points). To facilitate the identification of equivalent
2545               points in these separate tables, separate identifiers are
2546               defined.
2547;
2548
2549data_pd_calc_point_id
2550    _name                      '_pd_calc_point_id'
2551    _category                    pd_data
2552    _type                        char
2553    _related_item              '_pd_data_point_id'
2554    _related_function            alternate
2555    _definition
2556;              Arbitrary label identifying a calculated data point. Used to
2557               identify a specific entry in a list of values forming the
2558               calculated diffractogram. The role of this identifier may
2559               be adopted by _pd_data_point_id if measured, processed and
2560               calculated intensity values are combined in a single list.
2561;
2562
2563data_pd_data_point_id
2564    _name                      '_pd_data_point_id'
2565    _category                    pd_data
2566    _type                        char
2567    _definition
2568;              Arbitrary label identifying an entry in the table of
2569               diffractogram intensity values.
2570;
2571
2572data_pd_meas_point_id
2573    _name                      '_pd_meas_point_id'
2574    _category                    pd_data
2575    _type                        char
2576    _related_item              '_pd_data_point_id'
2577    _related_function            alternate
2578    _definition
2579;              Arbitrary label identifying a measured data point. Used to
2580               identify a specific entry in a list of measured intensities.
2581               The role of this identifier may be adopted by
2582               _pd_data_point_id if measured, processed and calculated
2583               intensity values are combined in a single list.
2584;
2585
2586data_pd_proc_point_id
2587    _name                      '_pd_proc_point_id'
2588    _category                    pd_data
2589    _type                        char
2590    loop_ _related_item
2591          _related_function
2592                               '_pd_data_point_id'            alternate
2593                               '_pd_meas_point_id'            alternate
2594    _definition
2595;              Arbitrary label identifying a processed data point. Used to
2596               identify a specific entry in a list of processed intensities.
2597               The role of this identifier may be adopted by
2598               _pd_data_point_id if measured, processed and calculated
2599               intensity values are combined in a single list, or by
2600               _pd_meas_point_id if measured and processed lists are
2601               combined.
2602;
2603
2604#eof-eof-eof-eof-eof-eof-eof-eof-eof-eof-eof-eof-eof-eof-eof-eof-eof-eof-eof
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