Hi If you have to use these techniques, the integral breadths are the one to use -- as Pam pointed out. Also keep in mind that the integral breadth produces a volume-weighted dimension. This is an apparent measure of the crystallite size parallel to the diffraction vector, and must be related to crystallite shape for overall crystallite dimensions to be resolved (see Langford & Louer's work on ZnO in JAC through the 80s & 90s). This also assumes that the crystallite size distribution is narrow.
Enjoy!! Regards, Nick ----- Original Message ----- From: "Whitfield, Pamela" <[EMAIL PROTECTED]> Date: Friday, June 30, 2006 11:29 pm To: rietveld_l@ill.fr > Stephane > > Just one small point - strictly speaking you should be using > integral breadth rather than FWHM for size/strain analysis. > > Pam > > -----Original Message----- > From: Von Dreele, Robert B. [mailto:[EMAIL PROTECTED] > Sent: June 29, 2006 2:24 PM > To: rietveld_l@ill.fr > > > Stephanie, > The GSAS routine REFLIST has an option to produce a "single phase > ascii" file of reflections. One of the columns in that file is > FWHM. Alternatively there is a graphic in EXPGUI (widplt) that will > plot FWHM and its Gaussian & Lorentzian contributions as a function > of 2-theta. Bob Von Dreele > > R.B. Von Dreele > IPNS Division > Argonne National Laboratory > Argonne, IL 60439-4814 > > > > -----Original Message----- > From: ruggeri [mailto:[EMAIL PROTECTED] > Sent: Thursday, June 29, 2006 12:17 PM > To: rietveld_l@ill.fr > > > Hello, > I am trying also to calculate crystal size from GSAS, and I want to > find back the fwhm of all the peaks from their position: how is it > possible? Thanks > > Stéphane Ruggeri, Ph.D. > Stagiaire post-doctoral > INRS Énergie, Matériaux et Télécommunications > 1650, boul. Lionel-Boulet > Varennes (Québec) > J3X 1S2 > Téléphone/Office : (450) 929 8139 > Télécopieur/Fax : (450) 929-8198 > > -----Message d'origine----- > De : [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] > Envoyé : 29 juin 2006 13:31 > À : rietveld_l@ill.fr > Objet : Crystal size in GSAS > > > Hi, > > I am wondering if GSAS calculates the crystal size? If not how can > I calculate the crystal size? I am using a profile type 3 function > (psedovoight) and obtaining the GU,GV,GW values as 0,0, 1.27 E+04 > for a Pt/C phase respectively. The Chi-square fit is 2.164. > Thankyou. > regards, > > Sajeev Moorthiyedath > > > >
