Dear Leonid, thank you very much. Indeed it is not "really simple": averaging procedure is not straightforward...
Now a question to Fullprof users: it seems that Fullprof is using non-standard designation for TCH PV parameters. I mean by standard the one which is adopted e.g. in D.Balzar et al., JAC 37, 911 (2004) - formula 8b, i.e. Gamma_L = x/cos(theta) + X/cos(theta) + Y*tan(theta), i.e. Lorentzian size broadening is given by X value. GSAS is also using this notation. In the Fullprof manual it is stated that the designation is opposite: Gamma_L = X*tan(theta) + Y/cos(theta) I am curious if this is still the case, or maybe by chance it was corrected in some recent Fullprof update? Sincerely, Maxim. -----Original Message----- From: Leonid Solovyov [mailto:[EMAIL PROTECTED] Sent: Thursday, November 13, 2008 12:32 PM To: rietveld_l@ill.fr Subject: RE: question on size-strain analysis Dear Maxim, Yes, these calculations can be done for TCH pV relatively simply (not “really simply” :-). The crystal size estimations from the refined parameters of TCH pV are included, for instance, into the DDM program [www.icct.ru/eng/content/persons/Sol_LA/ddm.html] and the formulae are described in Page 12 of the DDMguide. Note, however, that these estimations are valid only for simple crystal size distributions. Best regards, Leonid --- On Thu, 11/13/08, Maxim V. Lobanov <[EMAIL PROTECTED]> wrote: > From: Maxim V. Lobanov <[EMAIL PROTECTED]> > Subject: RE: question on size-strain analysis > To: rietveld_l@ill.fr > Date: Thursday, November 13, 2008, 6:47 AM > Dear colleagues, > > I would like first to thank everybody who responded to my > question on > Gaussian size broadening. > > And now would like to ask another closely related (but > "more practical") > question: > I think the easiest way to do particle size estimate in > case when one has > mixed alpha1/alpha2 (and/or a series of similar samples) is > to do Rietveld > or Le Bail fit and estimate particle size from the refined > profile > parameters (e.g. P and X in TCH PV). > But once you have refined values for both P and X, you > easily calculate > "Lorentzian size" and "Gaussian size" - > but (citing Woodward's lecture on > size-strain analysis), > "it is not immediately clear to me how to combine > these results and get an > accurate estimate of the crystallite size (though perhaps > there may be a > good way to do this)" > Can anybody suggest such "good way"? This must be > something really simple... > > Sincerely, > Maxim. >
