error in bond dissociation energy of gas phase molecule
chen... at gmail.com
Wed Apr 6 21:09:10 UTC 2011
Many thanks for the comments, Fawzi.
> That is exactly what I wanted to comment on:
> 1) GTH is a pseudopetential, and also has scalar relativistic
> correction (should be small in this case, but you never know)
I guess relativistic correction in O pseudopotential might be too
small to lower the binding energy by 0.5 eV. Possibly, something else
in the pseudopotential.
> 2) basiset for GTH pseudopotential are different from those on all
> electrons, they should be more or less comparable, but there is no
> guarantee, what can be compared is the basset limit in both cases
We used the same basis set as used in Gaussian (6-31g*). The basis
set convergence was checked in Gaussian, and the calculated binding
energy is the same as in literature.
> 3) a cutoff of 280 for OH is a bit on the low side, especially if you
> don't do any smoothing of the xc part, I would increase that
We did check this. Increasing the cutoff to 400 doesn't make a
In the all electron calculation, the cutoff seems even lower than 280
(directly taken from sample input without any change). We should check
this. But not sure this could be the cause of the increase of 0.8 eV
in binding energy. I am more concerned on the other settings for GAPW
calculations I don't understand.
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