EEL from Bethe-Salpeter

Deals with issues related to computation of optical spectra in reciprocal space: RPA, TDDFT, local field effects.

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

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javad
Posts: 42
Joined: Fri Feb 28, 2014 10:23 pm

EEL from Bethe-Salpeter

Post by javad » Thu Feb 25, 2021 9:49 am

Dear Yambo developpers

I have a question on the Bethe-Salpeter equation.
Is it possible to calculate EEL spectra from the BSE?
Shouldn't one use a different BSE with L instead of \bar L ?

How does Yambo deal with this problem?

best
javad
Javad Exirifard
IPM - Institute for Research in Fundamental Sciences
P. O. Box 19395-5746
Niavaran Square
Tehran, Iran

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Daniele Varsano
Posts: 3810
Joined: Tue Mar 17, 2009 2:23 pm
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Re: EEL from Bethe-Salpeter

Post by Daniele Varsano » Thu Feb 25, 2021 10:05 am

Dear Javad,
yes it is possible, both responses are implemented:

Code: Select all

L_kind=Lbar  ! \bar L
L_kind=full ! L
Note that the obtained eels spectra are the same, as the spectra are build consistently, what does change is the eigenvalues to the BSE, in the first case
the eigenvalues are the poles of eps_M, in the latter they are the poles of eels (1/eps_M).

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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