[Pw_forum] Optical phonon convergence at Gamma-point

[Paolo Giannozzi]

On May 24, 2009, at 23:04 , Sophia Nishad wrote:

> it is still off from the experiemntal value by ~8cm-1.

both pseudopotentials and approximations to the exchange-correlation
functional introduce intrinsic errors. It is quite hard to get any  
better
results than those you get.

Paolo
---
Paolo Giannozzi, Democritos and University of Udine, Italy