Wannier 90 interface in 4.5.2

[Daniele Varsano]

Dear Deyang,
but it is not entirely clear to me what quantity you are trying to compute.
As you know, solving the BSE provides the electron–hole amplitudes A^lambda_cvk that define each exciton. From these amplitudes, you can construct the excitonic wavefunction as a post-processing step. This is a two-particle wavefunction given by:

\Psi_exc^\lambda(re,rh) = \Sum_cvk A^lambda_cvk \phi_vk(r_v) \phi^*_ck(r_e)

where \phi are the KS states.

The A^lambda_cvk amplitudes are stored in the ndb.BS_diago database and they can be accessed using yambopy.

I hope this clarifies things

Best,
Daniele