Dear All,
I have three questions concerning GSAS.
I am in the middle of refinement of a strontium ferrite structure.
One of the neutron powder diffraction patterns contains 2 phases with
heavily overlapping lines. I want to find out the ratio of the phases.
My question are:
1. Are the phase fractions in the GSAS output expressed as weight or molar
fractions?
2. I have to introduce a constraint on the phase fractions:
f(phase1)+f(phase2)=1. I have one histogram.
I think it should have the form: "1,1 1.0 2,1 -1.0" Is it correct?
The third question concerns the definition of the magnetic structure in
GSAS. This aspect of the program is not very well covered in the manual. I
am using the latest release of the software for PC computers.
I refined the nuclear structure alone. Then defined the phase as
magnetic. The program should generate both nuclear and magnetic
reflections. I defined the magnetic moments of iron atoms and did not
change anything else (atom form factors). I passed the file through
Powpref without a problem. However, Genles returned the message:
"ISAM record with KEY="CRS1 SPNFLP" has problems Stop Program Terminated"
Am I missing some important parameter that needs to be set or just my
model is wrong?
Best regards
Marek
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Marek W. Schmidt
Department of Applied Mathematics
Research School of Physical Sciences and Engineering
Australian National University
Canberra ACT 0200, AUSTRALIA
email: [EMAIL PROTECTED]
facsimile: 61-2-6249 0732
telephone: 61-2-6249 0381
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Visit our website: http://rsphysse.anu.edu.au/appmaths
