optical spectrum

Concerns issues with computing quasiparticle corrections to the DFT eigenvalues - i.e., the self-energy within the GW approximation (-g n), or considering the Hartree-Fock exchange only (-x)

Moderators: Davide Sangalli, andrea.ferretti, myrta gruning, andrea marini, Daniele Varsano

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myrta gruning
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Re: optical spectrum

Post by myrta gruning » Wed Aug 19, 2015 11:33 am

Dear Samaneh

for the Bethe Salpeter it is important to correct accurately the states close to the gap/involved in the excitations.
yambo will use an extrapolation to get the correction for the other states (both core and higher conduction states).

In any case I would advise to check the convergence with parameters.

Best,
m
Dr Myrta Grüning
School of Mathematics and Physics
Queen's University Belfast - Northern Ireland

http://www.researcherid.com/rid/B-1515-2009

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Daniele Varsano
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Re: optical spectrum

Post by Daniele Varsano » Wed Aug 19, 2015 11:45 am

Dear Samaneh,
in general the number of bands entering to build up the excitonic matrix is different form the one you need to converge the polarizzability (screening).
In general you can avoid to include all the valence bands. I suggest you to do convergences studies including few valence and conduction bands and then increasing the windows until you get converged results (usually one is interest at the lower part of the spectrum).

Best,
Daniele

PS: fill the signature in your profile w9th your affiliation, avoiding then to include it in every post.
Dr. Daniele Varsano
S3-CNR Institute of Nanoscience and MaX Center, Italy
MaX - Materials design at the Exascale
http://www.nano.cnr.it
http://www.max-centre.eu/

samaneh
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Re: optical spectrum

Post by samaneh » Wed Aug 19, 2015 1:52 pm

Dear Dr Daniele and Dr Myrta,
Thank you for your quick replies
Best regards
S. Ataei
S. Ataei, PhD student at University of Tehran, Iran.

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