Dear QE users,
I have a question about e-ph lambda, calculated by "matdyn" program. I've found
that for some frequencies the quantity "(alpha)^2*F(w)/w" or "dos_a2F(w)/w" can
be negative, most probably because of the negative (imaginary) frequencies (I
can't believe a2F(w) become negative!). In "matdyn" program these negative
values are considered in lambda calculations. Should one remove these negative
values as these imaginary frequency modes can never exist in the system? then
where are those phonon branches? I think negative values of frequency can show
in some manner more strong electron structure interaction, so what do you
suggest one should do?
regards,
Ali
