TD-BSE calculations using the double-grid method?

Can't find a suitable forum for your query? Post it here.

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

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

TD-BSE calculations using the double-grid method?

Post by Dean » Fri Sep 11, 2020 9:37 am

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

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

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

Post by claudio » Fri Sep 11, 2020 9:55 am

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
Freely download scientific books from: http://www.freescience.info

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

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

Post by Dean » Mon Sep 14, 2020 1:50 am

Dear Claudio,
Thanks for your reply.
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.

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

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

Post by claudio » Mon Sep 14, 2020 9:48 am

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
Freely download scientific books from: http://www.freescience.info

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

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

Post by Dean » Tue Sep 15, 2020 2:32 am

Dear Claudio,
Thanks for your reply.
I am not clear about this sentence, “My advice is to converge first the independent particle case, and then use the same number of k-points in the GW and BSE.”
Do you mean convergence test of k-point in pw.x code first? I think that would be a very fast test.
Dr. Yimin Ding
Soochow University, China.

Post Reply