[Pw_forum] xspectra calculation
Matteo Calandra
matteo.calandra at impmc.jussieu.fr
Wed Oct 20 17:13:39 CEST 2010
>Dear Matteo,
>So when we just do the dipolar part, we don't need to care about the
>k vector, right?
yes, it is not used.
>Besides, in order to compare with an experimental spectrum, is it necessary to cut
>the occupied state below Fermi energy level within our Xspectra calculation ?
>In that case, we should set "cut_occ_states" = .true. and
>"ef_r" equal to the fermi energy we got in the scf calculation. Is it?
Yes. However if you have a small gap insulator, introduction of a
core-hole can lead to a metallic system (close the gap). In this case it is
not clear where to cut. Actually in this case the static core-hole
approximation is probably incorrect.
For metals it is even worst.
M.
Best regards,
Min Wu
2010-10
--
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Matteo Calandra, Charge de Recherche (CR1)
Institut de Minéralogie et de Physique des Milieux Condensés de Paris
Université Pierre et Marie Curie, tour 16, case 115
4 Place Jussieu, 75252 Paris Cedex 05 France
Tel: +33-1-44 27 52 16 Fax: +33-1-44 27 37 85
http://www.impmc.jussieu.fr/~calandra
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