Index

Core dictionary version 3.0.14

_cell.convert_Uij_to_betaij

Definition:

   
     The reciprocal space matrix for converting the U(ij) matrix of
     atomic displacement parameters to a dimensionless beta(IJ) matrix.
     The adp factor in a structure factor expression:
 
     t = exp -2pi**2 ( U11    h h a* a* + ...... 2 U23    k l b* c* )
     t = exp - 0.25  ( B11    h h a* a* + ...... 2 B23    k l b* c* )
   = exp -       ( beta11 h h + ............ 2 beta23 k l )
 
    The conversion of the U or B matrices to the beta matrix
 
     beta =   C U C   =    C B C /8pi**2
 
    where C is conversion matrix defined here.

Type: Real

Values appear in Matrix context.

Dimension: [3,3]

Evaluation method:

\
    With c  as  cell
 
    _cell.convert_Uij_to_betaij = \
                             1.4142 * Pi * Matrix([[ c.reciprocal_length_a, 0, 0 ],
                                                   [ 0, c.reciprocal_length_b, 0 ],
                                                   [ 0, 0, c.reciprocal_length_c ]])

Category:
cell