Dear All I have a query ragrdin phonon calculations at q=0. When I performed the phonon caclualtion at q=0, we didn't get zero enrgy for acoustic branches, however they can be set to zero by using acoustic/ crystal sum rules. My question is if the zone center acoustic braches values are too large (4 THz) even we have implemented very high convergence, it is ok to apply ASR.
Thanks -- Mayank BHABHA ATOMIC RESEARCH CENTER MUMBAI, INDIA Office: ?022-25595606 Home: 9920397437 / 9869834437