[Pw_forum] LO/TO and ASR

[Paolo Giannozzi]

On Sunday 26 June 2005 10:27, sun jason wrote:

> I'm not sure whether pw.x+ph.x can get the LO/TO splitting

of course you can: specify "epsil=.true." for the q=0 calculation,
so that the dielectric tenso and effective charges are calculated;
use code "dynmat.x" to add the non-analytic term for q=>0, and 
to impose the Acoustic Sum Rule...

> and the  whether this 38.497 cm-1 is TO mode?

...so that you can clearly that this is the translation mode
(having zero frequency after ASR is imposed)

-- 
Paolo Giannozzi             e-mail:  giannozz at nest.sns.it
Scuola Normale Superiore    Phone:   +39/050-509876, Fax:-563513 
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