Dear Jin, as I understand, you made leBail and Rietveld refinement on the same data. The difference in the cell can due to the fact that with Rietveld method the intensities of the peaks are not well determinate so the cell is different in order to compensate the intensity difference. suggestion: keep the LeBail cell for the Rietveld refinement and then refine the structure without refine the cell and profile parameters. After refine the cell and you should obtain the same result
Bests Davide From: rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] On Behalf Of Payzant, E. Andrew Sent: Wednesday, June 15, 2016 6:25 AM To: rietveld_l@ill.fr; Peng, Jin <jpe...@tulane.edu> Subject: Re: 答复: Le bail and rietveld method Probably the sample height has shifted due to thermal contraction. Not likely a zero shift. Andrew _____ From: Peng, Jin <jpe...@tulane.edu <mailto:jpe...@tulane.edu> > Date: June 14, 2016 at 7:55:29 PM EDT To: rietveld_l@ill.fr <mailto:rietveld_l@ill.fr> <rietveld_l@ill.fr <mailto:rietveld_l@ill.fr> > Subject: 答复: Le bail and rietveld method Low temperature x-ray diffraction on Powdered single crystals was taken from 5 to 80 degree with step size 0.02. The intensity of strongest peak is around 10000. Space group is Bb21m. The zero shift is quite large for both methods refinements. In GSAS, it is around -30. 发件人: rietveld_l-requ...@ill.fr <mailto:rietveld_l-requ...@ill.fr> [mailto:rietveld_l-requ...@ill.fr] 代表 Lucas Bonan Gomes 发送时间: 2016年6月15日 0:47 收件人: rietveld_l@ill.fr <mailto:rietveld_l@ill.fr> 主题: Re: Le bail and rietveld method Dear Jin, Tell us about the parameters used in the analysis, such as step size. Lucas Bonan Gomes. Em 14/06/2016 13:32, Peng, Jin escreveu: Dear Collegues: I am recently working on the structure refinement of some inorganic single crystals. I got the structure parameters from two ways: 1. Single crystal x-ray refinement; 2. Low temperature x-ray diffraction on Powdered single crystals. I refined the powder x-ray diffraction pattern with both rietveld method and Le bail method. However, the Le bail refinement result is consistent with single crystal x-ray while the rietveld show divergence. Both a, b, c are remarkably high than other two method. For example, c is 19.573 for single crystal xrd and 19.576 for le bail method. While for rietveld, it is 19.62. The powder x-ray pattern are taken from cuprate sample holder. I noticed that its peak position is around 0.15 degree lower (2theta) than the spectrum taken at glass sample holder. Jin ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Please do NOT attach files to the whole list <mailto:alan.he...@neutronoptics.com> <alan.he...@neutronoptics.com> Send commands to <mailto:lists...@ill.fr> <lists...@ill.fr> eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Please do NOT attach files to the whole list <alan.he...@neutronoptics.com> Send commands to <lists...@ill.fr> eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
