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International
Tables for Crystallography Volume G Definition and exchange of crystallographic data Edited by J. R. Hester and B. McMahon © International Union of Crystallography 2026 |
International Tables for Crystallography (2026). Vol. G. Early view chapter
https://doi.org/10.1107/97809553602060001011 Chapter 4.2 Core dictionary (coreCIF) |
Core dictionary version 3.3.0
_refine_ls.extinction_coef
Name:_refine_ls.extinction_coef
Aliases:
_refine_ls_extinction_coef
_refine.ls_extinction_coef
Definition:
The extinction coefficient used to calculate the correction
factor applied to the structure-factor data. The nature of the
extinction coefficient is given in the definitions of
_refine_ls.extinction_expression and _refine_ls.extinction_method.
For the 'Zachariasen' method it is the r* value; for the
'Becker-Coppens type 1 isotropic' method it is the 'g' value.
For 'Becker-Coppens type 2 isotropic' corrections it is
the 'rho' value. Note that the magnitude of these values is
usually of the order of 10000.
References:
Becker, P. J. & Coppens, P. (1974). Acta Cryst. A30,
129-147, 148-153.
Zachariasen, W. H. (1967). Acta Cryst. 23, 558-564.
Larson, A. C. (1967). Acta Cryst. 23, 664-665.
Example:| 3472(52) | Zachariasen coefficient r* = 0.347(5)e+04. |
Type: Real
Units: none
The permitted range is 0.0 → infinity
Category:
refine_ls
