Variable of ex-ph matrix element

Deals with issues related to electron-phonon coupling calculations

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

Post Reply
Posts: 27
Joined: Thu Jun 18, 2020 1:38 pm

Variable of ex-ph matrix element

Post by pangrt » Tue Mar 12, 2024 4:20 am

Dear all,
I am trying the ex-ph module, and my result seems to be that the ndb.excph_gkkp_fragment_1 EXCITON_PH_GKKP_SQUARED_Q1 matrix is generated by incident excitons, phonons and virtual excitons |g|. May I ask how or where the exciton Q and phonon q are set?

RongTianPang, Inner Mongolia University, Hohhot, China :)

User avatar
Posts: 460
Joined: Tue Mar 31, 2009 11:33 pm
Location: Marseille

Re: Variable of ex-ph matrix element

Post by claudio » Fri Apr 05, 2024 1:37 pm

Dear Pangrt

may you tell exactly which example are you following for the exicton-phonon?

In general Yambo automatically takes care of momentum conservation as Q' = Q-q or Q'=Q+q

But if you give me more information I can give you a better answer

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

Post Reply