[Pw_forum] convergence test for chromium

[Ary Junior]

Hi Lorenzo, I did exactly what you said and I got the same convergence chart
on both tests... I'm working with g-alumina and ultrasoft pp... My first
convergence test suggested an ecutwfc value between 50Ry-70Ry... Then I used
ecutrho = 280Ry for the second test... It means that I can use ecutrho =
4*ecutwfc, right?

[]s

Ary Junior

On Wed, Sep 30, 2009 at 1:00 PM, Lorenzo Paulatto <paulatto at sissa.it> wrote:

> In data 30 settembre 2009 alle ore 17:48:41, udayagiri sai babu
> <udayagiri3 at gmail.com> ha scritto:
>
> > Dear all
> > I did convergence tests for chromium. The ecut value i obtained for
> > energy converged to 1mRyd is 60Ryd! which i believe is very high for an
> > Ultra Soft PP can somebody tell me if i am doing something wrong. Given
> > below are my
> > sample input file and ecut vs total energy.
>
> Dear Udayagiri,
> what about the cutoff for charge density?
> One good procedure to find a nicely converged cutoff is to increase
> ecutwfc until it converges than set ecutrho to 4*ecutwfc and reduce
> ecutwfc keeping ecutrho fixed.
>
> Maybe you can fix ecutrho to 240 and see how low you can go with ecutwfc
>
> best regards
>
>
> --
> Lorenzo Paulatto
> SISSA  &  DEMOCRITOS (Trieste)
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