FYI, there is a separate BSE code for WIEN2k called BSE@WIEN2k.
It seems to require a cluster with hundreds of cores and a large amount
of memory as described on slide 23 in the document at:
http://www.wien2k.at/reg_user/textbooks/WIEN2k_lecture-notes_2013/DFT_advanced.pdf
It cannot be downloadable from Dr. C. Ambrosch-Draxl's old website
anymore as it no longer exists. However, you should be able to still
read about it on wayback:
https://web.archive.org/web/20120415092421/http://amadm.unileoben.ac.at/codes_wien2k.html
If your interested in it, I think you can try requesting it from Dr. R.
Laskowski:
http://www.mail-archive.com/wien%40zeus.theochem.tuwien.ac.at/msg03642.html
On 5/16/2015 12:28 AM, Xavier Rocquefelte wrote:
To properly describe an exciton, which is a two-particle entitie, you
need a two-particle theory at least.
DFT is a one particle theory, thus it is not suited to properly
describe excitonic effects.
For solids you must use the Bethe Salpeter Equation (BSE) which is
implemented in other codes and very expensive in terms of
computational time and memory. Another strategy is to mimick the
effect of the exciton on the optical properties using DFT and a
corehole approach. This last strategy is pragmatic and not exact, but
it allows to deals with this 2-particle problem using a one-particle
approach in a mean-field manner. Usually, a half corehole is used. It
corresponds to the Slater transition state and it gives nice results
in general. What kind of transtions are your doing? Does it implies
core states? If yes you can easily remove half an electron in the file
case.inc. If the transition is from valence states, the problem is
more tricky to solve.
Best Regards
Xavier
Dileep Krishnan <dil...@jncasr.ac.in> a écrit :
> Hi Users and Developers,
>
> I was calculating optical properties by OPTIC program. How can I add
> excitonic effects into the calculation?
>
> --
> Dileep Krishnan,
> Int. Ph. D Student,
> International Centre for Materials Science (ICMS),
> Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR),
> Jakkur, Bangalore-560064,
> INDIA.
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