[Pw_forum] Berry phase electric field calculations with empty bands

[Paolo Giannozzi]

On Nov 1, 2011, at 14:38 , Alexander Urban wrote:

> is it possible to perform Berry phase electric field calculations  
> for a
> periodic insulator including empty bands (1) in principle and (2)  
> using
> PWSCF?

based on my little knowledge of the subject, I would say (1) yes,
(2) likely no. It should be relatively straightforward to generalized
the current algorithms to work even in presence of unoccupied
bands (it is sufficient to consider the correct weight), but
i) it hasn't been done (or it hasn't been completed), and
ii) it must be done in a proper way, avoiding to increase
the complexity of the code.

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