difference BSEmod= "retarded" vs "resonant"

Deals with issues related to computation of optical spectra, in RPA (-o c) or by solving the Bethe-Salpeter equation (-o b). Includes local field effects, excitons, etc.

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michele guerrini
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Joined: Thu Mar 28, 2019 10:53 am

difference BSEmod= "retarded" vs "resonant"

Post by michele guerrini » Thu Jan 16, 2020 2:55 pm

Dear developers,
I have a very simple question to ask: what's in details the difference between the BSE mode = "retarded" vs BSE mode = "resonant" in terms of how the kernel is build up ?
Thank you!
Dr. Michele Guerrini
Humboldt-Universität zu Berlin
Institut für Physik und IRIS Adlershof
Zum Grossen Windkanal 6, 12489 Berlin, Germany
e-mail: guerrini@physik.hu-berlin.de
Skype: merlin__88

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Daniele Varsano
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Re: difference BSEmod= "retarded" vs "resonant"

Post by Daniele Varsano » Thu Jan 16, 2020 3:11 pm

Dear Michele,
the kernel is the same, what is different is how the dielectric function is built.
You can have a look at:

./src/bse/K_diago_compute_epsilon.F
./src/bse/K_output_file.F

Best,
Daniele
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/

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