[Pw_forum] Measure units in electron-phonon interaction

[sama at ns.dcci.unipi.it]

Thank you for the answer.
I am trying to obtain the electron-phonon coupling matrix el_ph_mat from
the subroutine elphel.
My question at the moment is:
el_ph_mat is the coupling with respect to the displacement patterns used
in the dynamical matrix generation?
In this case, in order to obtain the coupling with respect to the phonon
mode, it is sufficient to perform the following operation (do cycles are
implicit):

1.     g1(ik,ii,jj)=conjg(el_ph_mat(jbnd,ibnd,ik,ii))* &
                      el_ph_mat(jbnd,ibnd,ik,jj)

2.     g2(ik,ll) = g2(ik,ll) + DBLE(conjg(dyn(mu,ll)) * &
                   g1(ik,mu,vu) * dyn(vu,ll))


Thank you in advance,

Samantha Bruzzone
Dipartimento di ingegneria informatica, elettronica e delle telecomunicazioni
Univerista' di Pisa


>
> On Dec 3, 2010, at 18:13 , sama at ns.dcci.unipi.it wrote:
>
>> I'm not able to understand the measure unit of the transition matrix
>> element, as it is calculated from elphel subroutine.
>
> in the absence of different explicit specifications: everything
> should be in atomic units (Rydberg: e^2=2, \hbar=1, m=1/2)
>
> P.
> ---
> Paolo Giannozzi, Dept of Chemistry&Physics, Univ. Udine
> via delle Scienze 208, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
>
>
>
>
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