[Wien] Adding excitonic effects

[Xavier Rocquefelte]

Here is a document that can be usefull in which Peter discussed briefly "valence hole" for emission spectra: 
http://www.wien2k.at/reg_user/textbooks/WIEN2k_lecture-notes_2011/Blaha_xas_eels.pdf
Regards
Xavier

Dileep Krishnan <dileep at jncasr.ac.in> a écrit :

> Dear Xavier,
>
> Thank you very much for your quick and detailed reply. I am 
> calculating the valance optical properties, where the hole is 
> positioned in the valance states; JDOS, Energy loss function etc.
>
> Thanks
>
> ----- Original Message -----
> From: "Xavier Rocquefelte" <xavier.rocquefelte at univ-rennes1.fr>
> To: "A Mailing list for WIEN2k users" <wien at zeus.theochem.tuwien.ac.at>
> Sent: Saturday, May 16, 2015 11:58:08 AM
> Subject: Re: [Wien] Adding excitonic effects
>
>
> 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 <dileep at 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.
>> _______________________________________________
>> Wien mailing list
>> Wien at zeus.theochem.tuwien.ac.at
>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>> SEARCH the MAILING-LIST at:
>> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
>>
>
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> --
> 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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> Wien mailing list
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