Dear Rietveld's users, I have a question about GSAS: my TOF neutron diffraction profile exhibits a broadening of some low intense superstructure peaks where the index l is =2n+1 (tetragonal I cell). I'd like to do a refinement where this effect is taken in account. The superstructure is probably due to an ordering of vacancies in planes perpendicular to z-axis. I tried to use Stephens's function nÂ4 in GSAS, setting the anisotropic broadening axis to 0 0 2, and the other two vectors as 1 0 0 and 0 1 0 (because I should describe with three vectors the sub-lattice with sharp peaks, which has index l=2n, while the others are general); but my refinement doesn't work: the calculated profile presents very sharp peaks for all experimental peaks. What is my mistake? Thanks in advance, Marco Sommariva
-- Marco Sommariva Department of Materials Science University of Milano - Bicocca Via R. Cozzi 53 - 20125 MILAN, ITALY Phone +39.02.6448.5141 (5142) Fax +39.02.6448.5400 e-mail: [EMAIL PROTECTED]
