The Journal of Chemical Physics

On the low-lying states of MgO. II

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Using a double zeta plus polarization basis set of Slater orbitals, full valence MCSCF (FVMCSCF) calculations were performed for the low-lying states of MgO. For each state the FVMCSCF calculations were used to identify the important configurations which are then used in an MCSCF calculation and subsequently as references in a single and double excitation CI calculation. This approach is found to treat all states equivalently, with the maximum error in the computed Te's and Re's of 800 cm-1 and ∼0.03°, respectively. The b 3Σ+ state which has yet to be characterized experimentally is predicted to have a Te of ∼8300 cm-1 and a bond length of 1.79 Å. A spectroscopic analysis of the potential curves indicates that their shapes are in quite reasonable agreement with the range of experimental results. © 1981 American Institute of Physics.