Dear PWSCF developers.
I want to calculate absorption or dielectric (\epsion' or \epsilon'' ) of
materials
I know in order to get optical properties of materials accurately,
Bethe Salpieter equation is recommended, but for saving calculation
time,
we want to do more simple calculation.
Then, if the momentum operator matrix element ( or transition matrix
element <\phi_{c} | r| \phi_{v} > )
<\phi_{c}|p|\phi_{v}> (where \phi_{c} , \phi_{v} is conduction and valence
wave functions, respectively.
and p is the momentum operator )
can be calculated, I think dielectric function can be estimated.
Then, are there subroutine in PWSCF to calculate momentum matrix element in
order to estimate the
absorption or dielectric function.
Can XSpectra be used to estimate the absorption or dielectric function of
the materials ?
Sincerely, Yukihiro Okuno.
