On Feb 11, 2012, at 8:08 , KORIR KIPRONOH wrote: > I'm still seeking more clarification on the same subject, born > effective > charge is a product of "cell volume" with derivative of the > polarization > with respect to atomic displacement at zero macroscopic > field........so > I thought there is dependence on volume?
I am not sure I understand what you mean. If you have a finite object (or simply, a molecule) in a supercell, yes, the effective charges decrease as the volume of the supercell increases. This is normal: the dipole does not depend upon the volume of the supercell (if it is large enough), the dipole per unit volume does. P. --- Paolo Giannozzi, Dept of Chemistry&Physics&Environment, Univ. Udine, via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222
