[Wien] Representative number for O2 energy

[Veronica Ganduglia Pirovano]

I would  do exactly that see PRB 59, 15533 (1999)
I suggest an even higher cut off (30 Ry, at least!) for E_a and E_b.
I used 24 Ry and I know now that a somewhat larger cutoff gives an even 
larger
number for the atomization energy.  The expected number is approx 3.1 
eV/atom.
O has to be calculated in a NON-cubic box!  to get the right occupation!


L. D. Marks wrote:

>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).
>
>-----------------------------------------------
>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
>-----------------------------------------------
>
>_______________________________________________
>Wien mailing list
>Wien at zeus.theochem.tuwien.ac.at
>http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>
>  
>


-- 
------------------------------------------------------------
            Dr. M. Veronica Ganduglia-Pirovano
	    Humboldt-Universitaet zu Berlin
	    Institut fuer Chemie
Post:   Unter den Linden 6           
          10099 Berlin   

Besucher/   Brook-Taylor-Str. 2
Pakete:       12489 Berlin

Tel.:           +(49) 30-2093-7139
Fax:           +(49) 30-2093-7136
e-mail:     vgp at chemie.hu-berlin.de
-------------------------------------------------------------