Shortrange matrixelement

General discussion around the EPW software

Moderator: stiwari

Post Reply
ankit.gujarat
Posts: 7
Joined: Tue Sep 19, 2017 12:31 am
Affiliation:

Shortrange matrixelement

Post by ankit.gujarat »

Hi,
When calculating the shortrange electron-phonon matrix element, in the rotate_epmat.f90 in the subroutine rgd_blk_epw, the longrange part is first substracted from the total matrix element and if the shortrange tag is set to true, the magnitude of the longrange part is substracted once more.

epmat = epmat + facq*zaq*uq*bmat (where the signe is -1 i.e. longrange vertex is substracted)
&
if (shortrange) then
epmat = SQRT(epmat*conj(epmat) - epmatl*conj(epmatl))
end if

I donot understand why the longrange matrix element is substracted twice?
It will be really helpful, if someone can comment on this formulation.

Post Reply