[Pw_forum] Re: Different Gamma factors for Q-points in the same star

[Andrea Marini]

On Wed, 31 May 2006, Paolo Giannozzi wrote:

> On Wednesday 31 May 2006 12:23, Andrea Marini wrote:
>
>> So, unless I am doing something wrong in my calculations
>> (perfectly possible) there could be something wrong in the code.
>
> there is. If you perform the calculation of the Delta V and the
> calculation of electron-phonon coefficients in two separate steps,
> you get correct results (or, more exactly, results that are not
> obviously wrong). If however you perform the two calculations in
> a single step, you get incorrect results. This is true for all versions
> from 2.1 to 3.0 I think: version 2.0 didn't allow the single-step
> calculation, version 3.1 is correct in this respect (no warranty that
> it is correct in other respects, though).

Perfect ! Thanks. Now it works :) ... but ....

> Other questions about the symmetrization requires some more
> thought.

... again if you remove the call to the symmetrization routine symdynph_gq 
from elphon.f90 you get exactly the same Eliashberg function (tested 
with 4 4 4 and 6 6 6 MP grid). The gamma factors, instead,  are rotated in 
such a way to be the same for degenerate modes).

My problem remains. I need the gkkp elements and not their square modulus. 
While I can perfectly get them if the symdynph_gq routine is not called I 
have no idea how to define them from the output of symdynph_gq :(

Andrea

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                                Andrea MARINI

        Physics Department, University of Rome "Tor Vergata" (Italy)
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-- andrea.marini at roma2.infn.it - http://www.fisica.uniroma2.it/~marini/ --