[Pw_forum] phonon at Gamma point

Paolo Giannozzi giannozz at nest.sns.it
Tue Aug 22 14:33:05 CEST 2006

On Sunday 20 August 2006 00:36, Yansun Yao wrote:

>       Other than the internal coordinates, did you optimize the unit cell?

while a good thing in general, optimization of the unit cell is not needed
to have positive phonon frequencies at q=0, as long as atomic positions
are in equilibrium

Paolo Giannozzi             e-mail:  giannozz at nest.sns.it
Scuola Normale Superiore    Phone:   +39/050-509876, Fax:-563513 
Piazza dei Cavalieri 7      I-56126 Pisa, Italy

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