[Pw_forum] Improve convergence, slab and electric field.

[joaquin peralta]

Thanks, i obtain more fast convergence for 1V/A, but ...

If I use the previous results from 1V/A in order to calculate an increase in
the Field i obtain fluctuation in the energy.

     total energy              =    -261.46819272 Ry
     total energy              =    -261.46815798 Ry
     total energy              =    -261.46816720 Ry
     total energy              =    -261.46260676 Ry
     total energy              =    -261.37365516 Ry
     total energy              =    -261.46820680 Ry
     total energy              =    -261.46821935 Ry
     total energy              =    -261.46807352 Ry
     total energy              =    -261.46825528 Ry
     total energy              =    -261.46820900 Ry
     total energy              =    -261.46803348 Ry

for my case, is recommendable reduce the precision by default of the energy
convergence from 1D-4 to 1D-3? i mean with 3 decimal is good for me, but i
don't know if a similar scheme happen at different electric field.

Best Regards
Joaquín Peralta

On Tue, Aug 31, 2010 at 1:59 AM, Tone Kokalj <tone.kokalj at ijs.si> wrote:

> On Mon, 2010-08-30 at 14:43 -0500, joaquin peralta wrote:
> >
> > Sorry, I have now a slab put in the middle of the cell in the Z axis,
> > from z=32 to z=50 (maximum).
>
> I see. If the slab is located in the middle of the cell (i.e. at 0.5 in
> crystal units) then the dipole layer at 0.0 is OK!
>
> In this case here is the suggestion:
> Your 1 V/Angs is rather strong field. First perform SCF with lower field
> or no field (what Paolo suggested) and then use that as an input guess.
>
> Regards, Tone
>
> --
> Anton Kokalj
> J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
> (tel: +386-1-477-3523 // fax:+386-1-477-3822)
>
> Please, if possible, avoid sending me Word or PowerPoint attachments.
> See:  http://www.gnu.org/philosophy/no-word-attachments.html
>
>
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-- 
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Group of NanoMaterials
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http://www.gnm.cl
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Joaquín Andrés Peralta Camposano
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http://www.lpmd.cl/jperalta

In a world without frontiers,
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