Dipoles using the non-local part of the pseudo potential

Various technical topics such as parallelism and efficiency, netCDF problems, the Yambo code structure itself, are posted here.

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

Post Reply
Franz Fischer
Posts: 45
Joined: Wed Jul 20, 2022 9:36 am

Dipoles using the non-local part of the pseudo potential

Post by Franz Fischer » Tue Oct 22, 2024 2:36 pm

Dear developers,

I know that to correctly compute the single-particle v -> c transition dipoles for extended systems it is necessary to not only use the transition dipole in k-space, but also to add the commutator of the position vector r and the nonlocal part of the pseudo potential V^NL, i.e. i[V^NL, r].
I want to understand how this is handled in practice by yambo and thus I want you to guide me to the corresponding routine in the source code where this is done.

PS: I am using the Quantum Espresso interface to yambo.

Thanks in advance!

Best,
Franz
Franz Fischer
PhD student / IMPRS-UFAST fellow
Institute of Physical Chemistry
University of Hamburg

User avatar
Daniele Varsano
Posts: 4043
Joined: Tue Mar 17, 2009 2:23 pm
Contact:

Re: Dipoles using the non-local part of the pseudo potential

Post by Daniele Varsano » Fri Oct 25, 2024 9:04 am

Dear Franz,

the i[V^NL, r] commutator is taken into account unless the ns.kb_pp (produced by p2y) are renamed/deleted.
The commutator is evaluated in src/dipoles/DIPOLE_transverse.F routine.

Note that dipoles can also be calculated with the covariant approach (see DIPOLE_driver.F) (PRB 69, 085106 (2004)). In this case, the commutator is not needed.

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/

Franz Fischer
Posts: 45
Joined: Wed Jul 20, 2022 9:36 am

Re: Dipoles using the non-local part of the pseudo potential

Post by Franz Fischer » Mon Oct 28, 2024 1:31 pm

Cheers Daniele,

that helps a lot!

Best,
Franz
Franz Fischer
PhD student / IMPRS-UFAST fellow
Institute of Physical Chemistry
University of Hamburg

Post Reply