[Wien] Representative number for O2 energy

[L. D. Marks]

I would like to get a representative energy (i.e. not the correct one, but
one which is consistent with other calculations) for the O2 (molecule)
energy for an RMT of 1.6 and RKMAX of 7, GGA. (These values are what I am
using in some other calculations of bulk oxides, and the energy of O2
has a significant effect on the theoretical heats of formation.) Obviously
I cannot use these for the O2 molecule, the RMT has to be about 1.1. What
I have done is:
	a) Calculate O2 with RMT=1.1 RKMAX=5, ~30 a.u. cell: E_a
	b) Calculate O  with RMT=1.1 RKMAX=5, ~30 a.u. cell: E_b
	c) Calculate O  with RMT=1.6 RKMAX=7, ~30 a.u. cell: E_c
Then estimate the effective O2 energy as
	E_a - 2*E_b + 2*E_c

I would be interested to know if anyone has a better idea/method, apart
from using 2*E_c + an experimental number for the bond energy (or
meta-GGA).

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Laurence Marks
Department of Materials Science and Engineering
MSE Rm 2036 Cook Hall
2220 N Campus Drive
Northwestern University
Evanston, IL 60201, USA
Tel: (847) 491-3996 Fax: (847) 491-7820
email: L - marks @ northwestern . edu
http://www.numis.northwestern.edu
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