[Pw_forum] ph.x

[Paolo Giannozzi]

On Sun, 2014-01-12 at 13:55 +0330, shiva mokhavat wrote:

> I want to calculate phonon properties of cinnabar hexagonal structure
> of HgTe, but when I run ph.x some of the frequencies are negative. why
> this happen?

See http://www.quantum-espresso.org/faq/phonons/ , in particular 
items 7.3 and 7.2

P.
-- 
Paolo Giannozzi, Dept. Chemistry&Physics&Environment, 
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222