Dear All,

I am currently working on an open-shell open-shell complex, which can exist as 
either a doublet or a quartet spin state, both of which contain three unpaired 
electrons.  I am using a ROHF calculation which is then being used for 
orbitals  for a RS2 calculation, with a restricted CAS.  For the quartet, it is 
possible to obtain a good representation for the  wavefunction, with the ROHF.  
However, for the doublet I cannot obtain a good  initial guess at the 
wavefunction from the ROHF, as I cannot represent a doublet with three unpaired 
electrons.  The RS2 does recover from the poor initial wavefunction, to a 
degree, giving three orbitals with single occupancy, but the resulting energies 
do not tally to the separate monomer calculations.

Is there anyway of representing a doublet with three unpaired electrons, at the 
Hartree-Fock stage? 

Yours,

Tony Starkey



