[Pw_forum] momentum matrix element calculation in PWSCF

[Nicola Marzari]

Dear Yukihiro,


epsil.f90 (in QE) does what you ask, but probably it would be worth
investing in YAMBO or SaX (both public and interfaced with QE).

Note that the reconstruction of the AE wavefunction might be relevant.
Maybe others can comment on that ?

			nicola



On 2/16/11 7:33 AM, yukihiro_okuno at fujifilm.co.jp wrote:
>
> Dear PWSCF developers.
>
> I want to calculate absorption or dielectric (\epsion' or \epsilon'' )  of
> materials
>
> I know in order to get optical properties of materials accurately,
>
> Bethe Salpieter equation is recommended, but  for  saving  calculation
> time,
>
> we want to do more  simple calculation.
>
> Then, if the momentum operator matrix element ( or transition matrix
> element<\phi_{c} | r|  \phi_{v}>  )
>
>
> <\phi_{c}|p|\phi_{v}>   (where \phi_{c} , \phi_{v} is conduction and valence
> wave functions, respectively.
>
>                               and p is the momentum operator )
>
> can be calculated, I think dielectric function can be estimated.
>
> Then, are there subroutine in PWSCF to calculate momentum matrix element in
> order to estimate the
>
> absorption or dielectric function.
>
> Can  XSpectra be used to estimate the absorption or dielectric function of
> the materials ?
>
>
> Sincerely, Yukihiro Okuno.
>
>
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-- 
----------------------------------------------------------------------
Prof Nicola Marzari    Department of Materials    University of Oxford
Chair of Materials Modelling  Director, Materials Modelling Laboratory
nicola.marzari at materials.ox.ac.uk     http://mml.materials.ox.ac.uk/NM