A description of the extinction-correction method applied.
This description should
include information about the correction method, either
'Becker-Coppens' or 'Zachariasen'. The latter is sometimes
referred to as the 'Larson' method even though it employs
The Becker-Coppens procedure is referred to as 'type 1' when
correcting secondary extinction dominated by the mosaic spread;
as 'type 2' when secondary extinction is dominated by particle
size and includes a primary extinction component; and as 'mixed'
when there is a mixture of types 1 and 2.
For the Becker-Coppens method, it is also necessary to set the
mosaic distribution as either 'Gaussian' or 'Lorentzian' and the
nature of the extinction as 'isotropic' or 'anisotropic'. Note
that if either the 'mixed' or 'anisotropic' corrections are
applied, the multiple coefficients cannot be contained in
*_extinction_coef and must be listed in _refine.details.
Ref: Becker, P. J. & Coppens, P. (1974). Acta Cryst. A30,
Zachariasen, W. H. (1967). Acta Cryst. 23, 558- 564.
Larson, A. C. (1967). Acta Cryst. 23, 664-665.