Changes between Version 1 and Version 2 of LatticeComputations


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Timestamp:
Jul 5, 2010 6:34:58 PM (11 years ago)
Author:
toby
Comment:

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  • LatticeComputations

    v1 v2  
    99The unit cell is specified as a tuple of 6 values, corresponding to a, b, c in angstroms and alpha, beta and gamma as angles in degrees. Also used for these computations are the real and reciprocal lattice metric tensor (g and G, respectively) which are 3x3 tensors. Also used is an "A" tensor, which is closely related to the G tensor and is used to compute d-spacings from h,k,l values
    1010
    11   D^2^ = ''h''^2^*A(1) + ''k''^2^*A(2) + ''l''^2^*A(3) + ''h''*''k''*A(4) + ''h''*''l''*A(5) + ''k''*''l''*A(6)
     11  1/D^2^ = ''h''^2^*A(1) + ''k''^2^*A(2) + ''l''^2^*A(3) + ''h''*''k''*A(4) + ''h''*''l''*A(5) + ''k''*''l''*A(6)
    1212
    1313Somewhat confusingly, A and B are used to define a pair of 3x3 transformation matrices, where A*x converts Cartesian coordinates x into fractional ones and B does the inverse transform.