Re: question about the Scherrer method

[Miguel Hesiquio-Garduņo]

Hi I think that is very difficult obtain a free-strain material, and we can not  neglect this effect, and it is very useful work with integral breadth rahter tan FWHM, and you should use a reference material in order to obtain the breadth due the instrument, because if you only take in account the broadening observed in your sample, how do you know if the broadening observed is really due to microstructural effects or is due completely to the instrument?. Some years a go I did that, and when I measured a standard in the diffractometer and I observed that the broadening was too big and I had to change the slits in order to reduce the broadening. Best regards Miguel Hesiquio ----- Original Message ----- From: Angel L. Ortiz To: rietveld_l@ill.fr Sent: Friday, April 01, 2005 5:44 AM Subject: question about the Scherrer method Dear users of the Rietveld method:   I would like to launch a question regarding the use of the Scherrer method of line-broadening analysis. When estimating the crystallite size in a undistorted material (free of lattice microstrains) using Scherrer method, should I use the integral breadth of the pure profile or its full width at haft maximum (of course, both corrected by instrumental broadening)?. Why?.   Thanks in advance.   Angel Luis.