TD-BSE calculations using the double-grid method?

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Dean
Posts: 37
Joined: Thu Oct 10, 2019 7:03 am

TD-BSE calculations using the double-grid method?

Dear all,
Can I use double-grid method in the calculations of nonlinear properties(such as TD-BSE and second harmonic generation)?
Dr. Yimin Ding
Soochow University, China.

claudio
Posts: 265
Joined: Tue Mar 31, 2009 11:33 pm
Contact:

Re: TD-BSE calculations using the double-grid method?

No, for the moment it is not possible

best
Claudio
Claudio Attaccalite
[CNRS/ Aix-Marseille Université/ CINaM laborarory / TSN department
Campus de Luminy – Case 913
13288 MARSEILLE Cedex 09
web site: http://www.attaccalite.com

Dean
Posts: 37
Joined: Thu Oct 10, 2019 7:03 am

Re: TD-BSE calculations using the double-grid method?

Dear Claudio,
So, the k grid should be tested carefully when calculating the SHG of 2D materials?
In the papers (PRB,3,074003,2019), authors set a dense k-point, 24x24x1 for InSe but only 200 bands for GW-BSE calculations.
I want to know that k-point sampling is more important than the number of bands in GW-BSE or SHG calculations?
Dr. Yimin Ding
Soochow University, China.

claudio
Posts: 265
Joined: Tue Mar 31, 2009 11:33 pm
Contact:

Re: TD-BSE calculations using the double-grid method?

Dear Yimin Ding
a large number of bands is necessary to converge the dielectric constant
that enter in the definition of W and for the calculation of the GW corrections.
For the non-linear response, and the BSE you just need a small number of conduction and valence bands,
while convergence in k-point is more difficult.

My advice is to converge first the independent particle case,
and then use the same number of k-points in the GW and BSE.
For the number of conductions bands to use, it is best to test it in the linear response case that is faster

best
Claudio
Claudio Attaccalite
[CNRS/ Aix-Marseille Université/ CINaM laborarory / TSN department
Campus de Luminy – Case 913
13288 MARSEILLE Cedex 09
web site: http://www.attaccalite.com