Should I concern myself about X-ray absorption in Rietveld refinement
and sturcture solution from powder data? If so, is there way to input mass
attenuation coefficients into GSAS? I have read page 123 of the GSAS TECHNICAL
MANUAL and seems to say no. The Debye-Scherrer absorption function is
suggested only for "a weak absorber" and seems to be an arbitrary function
derived from neutron diffraction. The other functions are inappropriate for my
experimental conditions. Should I just refine thermal parameters, which are
presumed highly correlated with absorption, and not worry about it?
I am working with a strongly absrobing material, CuAlI4 in a Debye-Scherrer
geometry. I have used mucalc, on Brian Toby's NIST website
http://www.ncnr.nist.gov/programs/crystallography/mucalc.html
as earlier suggested by Lachlan Cranwick on this list.
Using the crystalographic density, Packed density = 6.673 (g/cc)
Wavelength = 0.9388 (A)
mu = 497.8 cm-1
Using 0.6 the crystalographic density, Packed density = 4.003 (g/cc)
Wavelength = 0.9388 (A)
mu = 298.6 cm-1
Thank you for any experience in this matter.
Roger
Roger Sullivan
Department of Chemistry, Box 8204
North Carolina State University
Raleigh, NC 27695
[EMAIL PROTECTED]
