MIXTURE (.cell)

Keyword type

Qualifier

Description

This keyword can be added to any line containing atomic coordinates in either POSITIONS_ABS or POSITIONS_FRAC data blocks to specify the characteristics of the component atoms in a disordered system. The format of the MIXTURE entry contains the index of the mixture atom and the weight associated with the given component. The example below contains three Al/Si mixture atoms for the 2:1 Al:Si ratio.

The following separators are allowed: SPACE, TAB, =, :, (, ).

Example

%BLOCK POSITIONS_FRAC
    Al    0.2500000000    0.5000000000    0.0000000000 MIXTURE:(   1  0.666667)
    Al   -0.2500000000   -0.5000000000    0.0000000000 MIXTURE:(   2  0.666667)
    Al    0.2500000000    0.0000000000    0.5000000000 MIXTURE:(   3  0.666667)
    Si    0.2500000000    0.5000000000    0.0000000000 MIXTURE:(   1  0.333333)
    Si   -0.2500000000   -0.5000000000    0.0000000000 MIXTURE:(   2  0.333333)
    Si    0.2500000000    0.0000000000    0.5000000000 MIXTURE:(   3  0.333333)
%ENDBLOCK POSITIONS_FRAC

See Also:

POSITIONS_ABS
POSITIONS_FRAC
CASTEP keyword glossary
CASTEP cell keywords and data blocks