Yambo Community Forum

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?

Thanks!
Pangrt

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

best
Claudio