I'm trying to run a calculation on the Os atom using the cc-pVDZ-PP basis set and ECP. The electronic configuration should be 5d^6 6s^2 and this seems to be what the AOs in the EHT set give (the following is output in define: reading orbital data d^6s^2(5D)).
However, when trying to define the starting guess the energies of the EHT orbitals suggest that the 6s orbital is higher in energy than the 5d orbitals. I manually occupied the 6s orbitals using the occupation number assignment menu. When I try to run this with dscf I get some convergence problems, mainly that the energy is oscillating all over the place, and I assume this is caused by occupying these higher energy orbitals.
Does anyone have any advice on how I might proceed? Should I be trying to generate a better starting guess, or is there some other trick to try?
