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[ha sa <ha_sadi@yahoo.com>]

Hi,

--- Anglade Pierre-Matthieu <anglade@gmail.com> wrote:

> 1) Have you checked the convergence on relaxed cells
> or unrelaxed one
> ? Relaxed surfaces usually takes more layers than
> unrelax slabs.

I did it on both for 100 surface and ,for both 5
layers were sufficient to get coverged surface
energies. 

> 2)  In my thesis I have computed the forces in
> unrelaxed slabs of
> tantalum with different surface orientation. It
> happens that for some
> surfaces the forces have a much larger depth than
> for others. For
> instance, in tantalum (a BCC metal) forces decreases
> much more slowly
> for [110] surface than for [111] (see  right figure
> in
> http://anglade.googlepages.com/these-anglade.pdf
> p61). This do not
> tell for sure that the relaxation will be stronger
> and that the number
> of layers must be higher. Yet it must be checked...
>
I got your point and I'll check the convergence.

thank you for your kind help.

> On 2/3/07, ha sa <ha_sadi@yahoo.com> wrote:
> > Hi,
> > I actually checked the convergence with respect to
> 100
> > surface and used the same values for 111 and 110
> > surfaces, but may be it is not sufficient for 110,
> I
> > shall try increasing no. of atomic layers. Thank
> you
> > very much for your help.
> >
> > --- Anglade Pierre-Matthieu <anglade@gmail.com>
> wrote:
> >
> > > Hi,
> > > it looks like your input  are fine. However are
> you
> > > sure they are
> > > converged with respect with respect to numbers
> of
> > > atomic layers
> > > (especially for the relaxed case) and energy
> cutoff
> > > ?
> > > regards
> > >
> > > PMA
> > >
> > > On 1/22/07, ha sa <ha_sadi@yahoo.com> wrote:
> > > > Dear abinit users,
> > > >   I calculated the surface energy for the
> three
> > > low
> > > > index surfaces for fcc transition metal ,the
> usual
> > > > results is to get the highest surface energy
> for
> > > 110
> > > > surface(most open structure) and the lowest
> for
> > > 111
> > > > surface (most close packed) my results are
> quite
> > > > normal except the following
> > > >           unrelaxed S.E.       relaxed S.E.
> > > > 110         3.19                  2.95
> > > > 100         3.06                  2.98
> > > > the unrelaxed surface energy is according to
> the
> > > > normal picture of fcc metal,but the relaxed
> > > surface
> > > > energy of 110 surface is slightly smaller than
> > > that of
> > > > 100 surface.
> > > > the above results were obtained using GGA, the
> > > > experimental surface energy for an average Ir
> > > surface
> > > > is 3.00 J/m^2. similar behavior is obtained
> usind
> > > LDA.
> > > >
> > > > I attached my input file for both surfaces.
> > > > What could be the source of this behavior?
> > > > thanks in advance.
> > > >
> > > > Hanan
> > > >
> > > >Hanan
> > > >
> > > >
> > >
> >
>
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> > >
> > >
> > > --
> > > Pierre-Matthieu Anglade
> > >
> >
> >
> >
> >
> >
>
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> 
> 
> -- 
> Pierre-Matthieu Anglade
> 



 
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