[Pw_forum] about elphon.f90

Antonio Sanna asanna at did.dsf.unica.it
Wed Mar 16 10:08:07 CET 2005

Dear Developers,

I'm tryng to obtain the electron-phonon coupling constants  g_kq  from 
the   subroutine "elphel" in  "elphon.f90",
I'm keeping:
     elphmat (jbnd, ibnd, ipert)           " 
elphmat(j,i)=<psi_{k+q,j}|dvscf_q*psi_{k,i}>  "

this, I think, is the coupling with respect to the phonon mode q (not to 
cartesian displacement of the atoms )  Is it right?

And also, in the subroutine that calculates the linewidths gamma:
after a summation over the fermi surface and a symmetrization, gammas 
are generate as
       gamma = gamma + real (conjg (dyn (mu, nu) ) * el_ph_sum (mu, vu) &
                     * dyn (vu, nu) )

what this transformation (dyn* elphsum dyn)  means?

Thank you in advance

Antonio Sanna

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