[Wien] calculation of electron-phonon coupling constant

[Dr. Emilio Orgaz]

Hello

I´m trying to evaluate the following Multiple Scattering formula which yield
the
tan of the phase shifts d at the energy E and raddi R.

tan d =(RK j'_l(KR) -b_l j_l(KR) ) / (RK n'_l(KR) -b_l n_l(KR) )

where b_l are the logarithmic derivatives of the radial function u_l at R
and E, K is
sqrt(E) and j, j' n, n' are the spherical bessel the r-derivative of the
spherical bessel
and the corresponding neumann functions.

Everything is tested and works pretty fine.

I tried to evaluate the  b_l (logarithmic derivatives of u_l) by means of
the "Potential Parameters"
obtained in lapw1 (sub atpar) employing the linear definition of u_l

u_l(r,E) = u_l(r,E_l) +(E-E_l) du_l/dE

Now, trying to reproduce the well known results for Nb, I obtained
significant differences in the phase-shifts.

I feel that I´m dropping out something in the u_l construction.
In the formal theory, u_l involves two constants A_l and B_l. In atpar they
are already considered?

Any help is acknowledged.

Emilio Orgaz

On 6/29/06, Peter Blaha <pblaha at theochem.tuwien.ac.at> wrote:
>
> In case.output1 you find the relevant "potential parameters", i.e.
> u_l(RMT), du/dr; du/de,...
>
> Otherwise, the routine   atpar.f   calculates the radial wavefunctions.
>
> Regards
>
> > I´m interested on the electron-phonon coupling constant calculated
> > a la Gaspari-Gyorffy. For this, I need the phase shifts for different
> > chanels.
> >
> > I know that those phase shifts can be obtained from the log-derivitives
> of
> > the radial function
> > u_l(r) at the MT radii.
> >
> > I would like to know how to extract  u_l(r) and the corresponding
> log-der
> > from WIEN2K code.
> >
> > thank you in advance for your help
> >
> > Emilio Orgaz
> >
> > On 10/13/05, Ashok Kumar Verma <hpps at magnum.barc.ernet.in> wrote:
> > >
> > > Dear WIEN users,
> > >              Is there anyone who can tell me how  to calculate the
> > > electron-phonon coupling constant using WIEN. I saw one paper by P.
> Blaha
> > > (PRB 62, 6774) where this has been done within the rigid muffin-tin
> > > approximation. But i dod not knos how to do it.
> > > thanking in advance
> > >
> > >
> > >
> > > _______________________________________________
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> > > Wien at zeus.theochem.tuwien.ac.at
> > > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
> > >
> >
> >
> >
> > --
> > Dr. Emilio Orgaz
> > Departamento de Física y Química Teórica
> > Facultad de Química, UNAM
> > Emilio.Orgaz at gmail.com
> > Tel.  5622-3776
> > Fax. 5622-3521
> >
>
>
>                                       P.Blaha
> --------------------------------------------------------------------------
> Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
> Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
> Email: blaha at theochem.tuwien.ac.at    WWW:
> http://info.tuwien.ac.at/theochem/
> --------------------------------------------------------------------------
> _______________________________________________
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>



-- 
Dr. Emilio Orgaz
Departamento de Física y Química Teórica
Facultad de Química, UNAM
Emilio.Orgaz at gmail.com
Tel.  5622-3776
Fax. 5622-3521
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