Gw+bse optical properties

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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mjakhar7665
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Joined: Tue Jan 19, 2021 11:12 am

Gw+bse optical properties

Post by mjakhar7665 » Sat Feb 13, 2021 5:53 pm

Hello sir,
I am new in yambo
i trying to calculate the optical absorbance of 2D stystem
Please check my input file for BSE with GW corrections, many peoples using the coulomb cutoff factor but i don't, Please suggest me about this.

First i calculate the GW then BSE, After doing the BSE i get many files (attached below) i don't understand which is for optical absorbance (not imaginary)
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Mukesh Jakhar
Central University of Punjab
Bathinda India

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Daniele Varsano
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Re: Gw+bse optical properties

Post by Daniele Varsano » Sat Feb 13, 2021 8:01 pm

Dear Mukesh,

in the o.eps_q1_* file your have the macroscopic dielectric function.
There you can find in 2nd and 3rd column the imaginary and real part of epsilon. The other two columns are the same at independent particle level.
If you are interested n the absorbance you can evaluate from the real and image part of epsilon calculating refractive index and extinction coefficient.

About the cutoff of the Coulomb interaction have in mind that GW gap and binding energies converge very slowly with the vacuum, while for the excitation energies the two effects somehow compensate and probably you can reach convergence with a reasonable cell size.

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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