XABS2

4.33 - XABS2 - Empirical Absorption Correction

Synopsis
XABS2 is a program to calculate empirical absorption corrections from the calculated and observed structure factors. The original XABS (H. Hope and B. Moezzi, Jul83, Feb84, May85) obtained 12 coefficients from a linear least-squares fit in sin**2(theta) to (1/A vs sin**2(theta)), by minimizing weighted differences between Fo^2 and Fc^2. XABS2 calculates either 24, 18 or 12 coefficients from a least-squares fit of (1/A vs sin**2(theta)) to either a cubic, quadratic or linear equations in sin**2(theta) by minimization of Fo^2 and Fc^2 differences. You can choose whether to do a linear, quadratic or cubic fit. A cubic fit is better for Cu Ka radiation with data to 2theta > 90 degrees. A linear fit is better for Mo Ka or Cu data that has a restricted resolution, such as in macromolecular crystallography.

The program XABS2 is written by Sean Parkin et al.

Files read
  1. name.FCF - written by SHELXL (LIST 4, MERG 0 instructions, based on ISOTROPIC refinement).
  2. name.INS - for unit cell information only.
Files written
  1. XABS2.HKL - absorption corrected reflection file
  2. XABS2.LST - List file giving summary of the applied corrections
  3. XABS2.CIF - CIF containing relevant information