Re: CCL:G:Singlet Oxygen with UHF

[Anatoli Korkin <korkin-0at0-qtp.ufl.edu>]

 >
 > > Hi,
 > > can anybody please tell me how to compute the lowest singlet state
 > > of the oxygen molecule (singlet-Delta_gerade, 0.984 eV above the
 > > triplet-Sigma_gerade ground state) with the UHF method ?
 >
 The ACES II program has two-determinat coupled-cluster method.
 You will get in a consistent way both right energies and wave functions
 for the lowest triplet and both singlet states. The type of the
 reference function is not important if you do not care about a
 spin contamination. Technically you can use the orbitals from ROHF
 or UHF solution for the triplet oxygen.
 For theory look: A. Balkova, R.J. Bartlett, J. Chem.Phys. Lett., 1992,
 193, 364, and references therein.
 For some recent examples: A.A. Korkin, A. Balkova, R.J. Bartlett,
 R.J. Boyd, P.v.R. Schleyer, J. Phys. Chem. 1996, 100, 5702.
 To get the ACES program contact Prof. Rodney J. Bartlett
 (bartlett-0at0-qtp.ufl.edu)
 or Dr. Ajith Perera (perera-0at0-qtp. ufl.edu).
 Anatoli Korkin
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