At least, in the classical article by Peter Stephens (J. Appl. Cryst., 32, 281) it is written about this and similar approaches that "these methods have been successful in producing improved line-shape fits, even though no theoretical justification or microscopic model has been given". The description is given in the GSAS manual. I asssume this is a phenomenological treatment, which appears quite reasonable and convenient... By the way, GSAS has Stephens' formulation as well. Sincerely, Maxim. > > i have a question about the GSAS software. Indeed, i would like to know >what are exactly the L11, L22, L33....L23 parameters. I saw that these >parameters represent the anisotropic microstrain in material. Moreover, >there is an empirical expression which uses these parameters as following : > > L22*k^2 + L33*l^2 + 2*L12*hk + 2*L13*hl + 2*L23*kl > > I would like to know and understand the physical representation of these >parameters and this expression. >
__________________________________ Maxim V. Lobanov Department of Chemistry Rutgers University 610 Taylor Rd Piscataway, NJ 08854 Phone: (732) 445-3811
