[Pw_forum] Improve convergence, slab and electric field.

[joaquin peralta]

Thanks for the answers.

In my case i'm using Vanderbilt ultrasoft pseudopotential Al.pbe-n-van.UPF.
I assume that a small cutoff could be used in this case. Or not?

My cell in this case are specified in bhor and atom positions in angstrom.

ATOMIC_POSITIONS (angstrom)
Al   4.295143   -2.479802   43.5
Al   5.726858   -3.306403   41.689899
Al   1.431714   -0.826601   41.689899
Al   2.863429   -3.306403   41.689899
Al   4.295143   -0.826601   41.689899
Al   2.863429   -1.653201   39.351919
Al   7.158572   -4.133004   39.351919
......
CELL_PARAMETERS {cubic}
10.822192        0.000000        0.000000
5.411096         -9.372293       0.000000
0.000000         0.000000        139.892407
.......

Sure are the most inappropriate cell parameters, but in the case of a slab
in the center of a big cell, I use this for simplicity with my previous cell
data.

By the way, when change my nbnd to 200, the disk-space used increase to
28Gb.

Will be better increase the cutoff of the potential and reduce kpoints or
others things?

Thanks for the answers,

Joaquin Peralta.

On Fri, Aug 27, 2010 at 12:42 PM, Paolo Giannozzi <giannozz at democritos.it>wrote:

>
> On Aug 27, 2010, at 19:06 , Guda Karthik wrote:
>
> > The celldm(1) cannot be 1.0
>
> actually it can be any value, as long as the primitive
> vectors are consistent. Not a good idea, though. I
> never understood why among the 1001 available
> methods to specify a crystal cell, the most popular
> are invariably the most awkward
>
> P.
> ---
> Paolo Giannozzi, Dept of Physics, University of Udine
> via delle Scienze 208, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
>
>
>
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-- 
----------------------------------------------------
Group of NanoMaterials
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http://www.gnm.cl
----------------------------------------------------
Joaquín Andrés Peralta Camposano
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http://www.lpmd.cl/jperalta

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