ABSORPTION CORRECTION TOOLS PLATON HOMEPAGE

Related keyboard instruction: **ABSG mu (nx ny nz) (NOCHECK)(LIST)**

See also Absorption Correction Menu

Absorption correction based on face indexing and integration on a Gaussian grid.

The modified Coppens code (see Crystallographic Computing, 1970) has been implemented in PLATON and adapted to fit into the direction cosine regime introduced with SHELX-76 (compatible with SHELXL97).

Two files are needed:

**name.ins**: instruction file

**name.hkl**: reflection file (h,k,l,F^2,sig(F^2) + direction cosines)

with SHELXL HKLF 4 format (3I4, 2F8.2,I4,6F8.5).

PLATON/ABSG instruction file format:

TITL text

CELL lamda a b c alpha beta gamma

FACE h k l d

...(etc)...

HKLF 4

ABSG mu (nx ny nz)

**Notes:**

- d is the distance to a choose reference centre inside the crystal
- the dimensions of mu and d should be the same
(i.e.
**mm**or**cm**and their corresponding reciprocals) - nx, ny & nz are the 'Gauss grid numbers in the x, y & z direction
respectively.

The Gauss numbers can be omitted or set to even numbers (e.g. 8).

High values (e.g. 32) should give accurate values similar to those obtained with**ABST**. However, computing time increases rapidly with increasing Gauss number values. - Analytical integration in place of Gaussian integration can be done by substituting the last instruction by 'ABST mu ',

PLATON/ABSG may be run for **name.ins** through:

platon name.ins

The corrected data are written to (SHELX HKLF 4 style):
**name.hkp**

See ABST for test data and EXAMPLE DATA.

ABSORPTION CORRECTION TOOLS PLATON HOMEPAGE