Dear all, I would appreciate any comments for the following problem.
I have been studying samples (ABO2) with a rather simple R -3 m structure. Although I had expected their neutron powder diffraction refinement should be simple, I encountered a strange problem. Many of the peak positions are quite off from where they should be. For instance, I singled out and refine (0 0 3), (0 0 6), (0 0 9) & (0 0 12) separately. Quite strangely, (0 0 6) peak is noticeably off when (0 0 3), (0 0 9) and (0 0 12) are good. For full refinements, such problem shows up for several peaks. I see same trend from data measured at two different instruments: CW and TOF. FYI, the peak profiles are quite Lorentzian and asymmetric. Anybody have experiences such a problem, and/or have suggestions what is going on? I would greatly appreciate. Jae-Ho ************************************* Jae-Ho Chung, Ph.D. NIST Center for Neutron Research 100 Bureau Drive, Stop 8562 Gaithersburg, MD 20899-8562 Tel. 301-975-8369 (office) 301-975-5085 (SPINS) 240-506-8389 (cell) Fax. 301-921-9847 e-mail: [EMAIL PROTECTED] (work) [EMAIL PROTECTED](personal) *************************************