Index

Core dictionary version 3.3.0

_refine_ls.extinction_method

Definition:

   
    A description of the extinction correction method applied with the
    data item _refine_ls.extinction_coef. 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 Zachariasen's formula.

    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 are 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 the
    _refine_ls.extinction_coef and must be listed in _refine.special_details.

    References:
      Becker, P. J. & Coppens, P. (1974). Acta Cryst. A30, 129-153.
      Zachariasen, W. H. (1967). Acta Cryst. 23, 558-564.
      Larson, A. C. (1967). Acta Cryst. 23, 664-665.

Type: Text

Category:
refine_ls