[Pw_forum] Cr GGA potential is underestimating the cohesive energy.

[udayagiri sai babu]

Thank you dear Paolo for the reference you provided me.

On Sat, Oct 17, 2009 at 4:07 PM, Paolo Giannozzi <giannozz at democritos.it>wrote:

>
> On Oct 17, 2009, at 11:31 , udayagiri sai babu wrote:
>
> > I am calculated the cohesive energy of Cr using the pseudopotential
> > Cr.pbe-sp-van.UPF. I got is 3.63 ev/atom as the cohesive energy
> > where as the experimental value is 4.1 ev/atom. As i know the GGA
> > pseudopotential should overestimate the cohesive energy value
>
> should it? LDA overestimates, GGA not necessarily so.
>
> The cohesive energy of Cr has been already calculated by many authors,
> for sure. You may want to have a look at what other people have done
> before you. For instance, here:
> http://dare.ubvu.vu.nl/bitstream/1871/9949/1/B4.pdf
> (found in 5' of google search). They get 3.58eV for Becke-Perdew,
> 3.80eV for Perdew-Wang. So 3.63eV for PBE after all is not that bad.
>
> 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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-- 
U.Saibabu
PhD student,
Deformation mechanisms modeling group,
Materials engineering department,
IISc Bangalore,
India.
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