Yambo Community Forum

Dear developers
I have a question about the data structure of excitondb.py
From code I excitondb.py, I know I can read exciton wavefunction with yambopy.Exciton eigenvectors are arranged as eigenvectors[i_exc, i_kvc]
Transitions are unpacked in table[ i_k, i_v, i_c, i_s_c, i_s_v ].This works well with q=0 exciton. However,when it comes to q!=0 exciton, the meaning of index i_k becomes vague ,whether it refers to electron momentum or hole momentum?
Best wishes!

Dear Yunfei,

Technically the index "ik" refers to the "electron" momentum.

This depends on the yambo convention for electron-hole transitions: in yambo, an exciton at transfer momentum q is calculated with transitions like (vk' --> ck) where k' = k-q. The index "ik" refers to "k" in this scheme.

Cheers,
Fulvio