[Pw_forum] dipole correction-dipole field keep constant during optimization

[Fenggong Wang]

Dear Guido,
       Thank you very much for your advice.
        Yes, it is a slab. The problem is it is difficult to converge if
the dipole correction is added because in our system the charge density is
changing too abruptly. Therefore, I was wondering whether adding a dipole
correction which is keep constant during the scf convergence can improve
the convergence problem. Of course, this will depends very much on the
initial value of the dipole field.
        Fenggong

On Tue, Oct 9, 2012 at 3:41 AM, Guido Fratesi <fratesi at mater.unimib.it>wrote:

> Dear Fenggong,
>
> I assume you are computing properties for a 2D system such as a slab, or
> 0D such as molecule-in-a-box.
>
> You can use variables in input (Doc/INPUT_PW):
>   tefield (necessary in any case below)
>   dipfield for a scf correction (which is determined by density)
>   eamp /= 0 to add a constant value added.
>
> I you want to dig into the code, PW/src/add_efield.f90 is the routine of
> your interest.
>
> Hope this helps,
> Guido
>
> On 10/08/2012 06:34 PM, Fenggong Wang wrote:
> > Dear Everyone,
> >         I am relatively new to Quantum Espresso.
> >         Could we keep the dipole field at a constant value during the
> > scf interations or constaint it to be in a value range when adding the
> > dipole correction in pwscf? Which part of the code should we refer to
> > for this? Any guidance or comments on this?
> >        Thank you very much.
> > Fenggong
> >
> > --
> > Dr. Fenggong Wang
> > Postdoctoral Researcher
> >
> > Department of Chemistry
> > University of Pennsylvania
> > 231 South 34th Street, BOX 314
> > Philadelphia, PA 19104-6323
> > e-mail: wangfenggong at gmail.com <mailto:wangfenggong at gmail.com>;
> > fenggong at sas.upenn.edu <mailto:fenggong at sas.upenn.edu>
> >
> >
> > _______________________________________________
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> >
>
> --
> Guido Fratesi
>
> Dipartimento di Scienza dei Materiali
> Universita` degli Studi di Milano-Bicocca
> via Cozzi 53, 20125 Milano, Italy
>
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>



-- 
Dr. Fenggong Wang
Postdoctoral Researcher

Department of Chemistry
University of Pennsylvania
231 South 34th Street, BOX 314
Philadelphia, PA 19104-6323
e-mail: wangfenggong at gmail.com; fenggong at sas.upenn.edu
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