[Pw_forum] Cohesive Energy of N2 molecule

[Giovani Faccin]

Dear Izaak,

Looking at your input file, a few things to try out came to mind:

1 - Did you try to integrate using more k points? Experiment with, say,
3x3x3 K points and see if anything changes.

2 - Try the calculation with  ecutrho   = 360, see if anything changes.

Hope it might help.

Giovani M. Faccin
UFMS - Brazil

2011/5/3 Izaak Williamson <izaakw89 at yahoo.com>

> Dear all,
>
> I am trying to calculate the cohesive energy of the N2 molecule using the
> attached input file (relax.in) and am getting a value of -16.57 eV. I use
> DFT with GGA and the pseudo-potential N.pbe-rrkjus.UPF. Other work [Fuchs
> et. al., Phys. Rev. B 65, (2002)245212] has performed similar calculations
> and obtained values ~10.5 eV. They even list an experimental value of 9.76
> eV. Why is my value so much higher? Is there anything in my input file that
> could be giving inaccurate results? Is it my pseudo-potential that is
> causing this problem?
>
> Thanks for any help.
>
> --
> Izaak Williamson
> Research Assistant
> Physics Department
> Boise State University
>
>
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>


-- 
Giovani
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