Index

Core dictionary version 3.3.0

_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 [ - 2π^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* ) ]
    t = exp [ -       ( β11 h h + ............ 2 β23 k l ) ].

    The conversion of the U or B matrices to the β matrix

    β =   C U C   =    C B C /8π^2^

    where C is the conversion matrix defined here.

Type: Real

Values appear in Matrix context.

Dimension: [3,3]

Units: reciprocal_angstroms

Evaluation method:

    With c  as  cell

    _cell.convert_Uij_to_betaij =
    Sqrt(2) * Pi * Matrix([[ c.reciprocal_length_a, 0, 0 ],
                          [ 0, c.reciprocal_length_b, 0 ],
                          [ 0, 0, c.reciprocal_length_c ]])

Category:
cell