>Uii should be positive and greater than 0 to make physical sense.
Yes. In particular Uij should be a positive definite matrix. If Uii is
negative it means that some systematic error is being soaked up there
eg lack of an absorbtion correction will reduce the apparent temperature
factor, sinc
I do not know bout Lij but Uij can be negative -- However only when "i" is not equal
"j".
Uii should be positive and greater than 0 to make physical sense. Moreover,
there are other restrictions too and I can find them if you are interested.
Dr. Peter Y. ZavalijUniversity Crystallographer
Dear all,
I am working with GSAS for structure refinement. I am new in the field. So I
probably have some silly questions. When I introduce anisotropic thermal
parameters (U11, U22, ... U23) some of them are negative. Is this possible?
Should I always refine U12, U13 and U23? I used the third pea
