[Pw_forum] lambda

[Paolo Giannozzi]

On Thursday 07 July 2005 12:42, Aritz Leonardo wrote:

> I have been searching the archive to know why am I obtaining negative
> values of lambda and gamma

you didn't search very well:

http://www.democritos.it/pipermail/pw_forum/2004-September/001316.html

The calculation of electron-phonon coefficients is quite tricky and 
involves complex symmetrization operations. I don't know exactly 
where negative values can come from, but I have never noticed 
anything wrong in the calculation.

In any event, if you get negative values of lambda and gamma, you
are seriously far from convergence.

Paolo

-- 
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