Hi Apu,
Your peak looks super-Lorentzian. Super-Lorentzian peak can be due to bimodal distribution (Young, R. A. & Sakthivel, A. (1988). J. Appl. Crystallogr.21, 416-425.) or wide Lognormal distribution (Popa, N. C. & Balzar, D. (2002). J. Appl. Crystallogr.35, 338–346.). In the latter case, Popa et al. directly refine mean and standard deviation of crystallite size distribution to the profile. His model has been put into TOPAS (Wang, X., Li, J., McDonald, R. G., Van Riessen, A. & Hart, R. D. (2015). J. Appl. Crystallogr.48, 814–826.) Cheers! P.S. No one is allow to send attachments to Rietveld_I list. You need to paste their links instead. -- Yours Sincerely, Dr. Xiaodong(Tony) Wang XRD Application Scientist Bruker Singapore Pte. Ltd. At 2015-06-15 14:29:28, "Patrick Weisbecker" <weis...@yahoo.fr> wrote: Apu, I would try bimodal distribution of crystallite sizes: in fullprof you can use two phases with the same structure and different peak shape and broadening. Regards, Patrick -------------------------------------------------------------------------------------------- Patrick Weisbecker Laboratoire des Composites ThermoStructuraux (LCTS) 3 allée de la Boétie 33600 PESSAC-France De : Apu Sarkar <apusar...@gmail.com> À : "rietveld_l@ill.fr" <rietveld_l@ill.fr> Envoyé le : Lundi 15 juin 2015 7h59 Objet : Peak assymtery not able to fit Hi, I am working on a nanocrystalline Nickel sample. I am not able to fit the peaks to get FWHM and Integral Breadth. Please see the attached images. Fig. 1 shows the profile and a zoomed view of a peak. Tail part of the peak is broader. Fig. 2 shows the winplotr fit. It is not matching the max intensity. Please give you suggestions to get a better fit for this kind of XRD peak. Thanks Apu ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 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/ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
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