Thank you dear Paolo for the reference you provided me.<br><br><div class="gmail_quote">On Sat, Oct 17, 2009 at 4:07 PM, Paolo Giannozzi <span dir="ltr"><<a href="mailto:giannozz@democritos.it">giannozz@democritos.it</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div class="im"><br>
On Oct 17, 2009, at 11:31 , udayagiri sai babu wrote:<br>
<br>
> I am calculated the cohesive energy of Cr using the pseudopotential<br>
> Cr.pbe-sp-van.UPF. I got is 3.63 ev/atom as the cohesive energy<br>
> where as the experimental value is 4.1 ev/atom. As i know the GGA<br>
> pseudopotential should overestimate the cohesive energy value<br>
<br>
</div>should it? LDA overestimates, GGA not necessarily so.<br>
<br>
The cohesive energy of Cr has been already calculated by many authors,<br>
for sure. You may want to have a look at what other people have done<br>
before you. For instance, here:<br>
<a href="http://dare.ubvu.vu.nl/bitstream/1871/9949/1/B4.pdf" target="_blank">http://dare.ubvu.vu.nl/bitstream/1871/9949/1/B4.pdf</a><br>
(found in 5' of google search). They get 3.58eV for Becke-Perdew,<br>
3.80eV for Perdew-Wang. So 3.63eV for PBE after all is not that bad.<br>
<br>
P.<br>
---<br>
Paolo Giannozzi, Dept of Physics, University of Udine<br>
via delle Scienze 208, 33100 Udine, Italy<br>
Phone +39-0432-558216, fax +39-0432-558222<br>
<br>
<br>
<br>
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</blockquote></div><br><br clear="all"><br>-- <br>U.Saibabu<br>PhD student,<br>Deformation mechanisms modeling group,<br>Materials engineering department,<br>IISc Bangalore,<br>India.<br><br>