Dear QE users, Referring to example07 about electron-phonon cooupling, the calculation ends up finding nonzero line-widths (gamma) at q=0 (printed in elph. 0.000000. 0.000000. 0.000000 file). I find this rather odd, since the electron-phonon matrix elements "g" should vanish at q=0. This can be seen from the explicit form of the interaction term in Fourier expansion, which contains a dot product of q with the phonon polarization vector.
Could anyone explain the reason for the nonzero values? Could it be related to the fact that at q=0 acoustic sum rules not enforced in the calculation of the line-width? Regards, Burak Himmetoglu Post-Doctoral Associate Materials Department University of California at Santa Barbara CA 93106 -------------- next part -------------- An HTML attachment was scrubbed... URL: http://pwscf.org/pipermail/pw_forum/attachments/20130613/85da3b59/attachment.html
