THEORETICAL DESCRIPTION OF THE LOW-LYING VALENCE STATES OF THE MGC MOLECULE

Restricted Hartree-Fock (RHF) and generalized valence bond (GVB) calcu lations, plus configuration interaction (Cl), have been performed for four electronic valence states [(3) Sigma(-) (1), 5 Sigma(-) (2), 3 Pi , (3) (3) Pi (4)] of the MgC molecule. Their energies have been calcul ated, in the range from 1.5 to 15.0 Angstrom. From the potential curve s spectroscopic constants have been obtained and the respective produc ts of dissociation well characterized. The GVB wavefunctions allowed u s to understand the bonding details and to identify the stabilization effects for the different states of the molecule. The (3) Sigma(-) Sta te was found to be the ground state, in agreement with previous calcul ations, with the (5) Sigma(-)lying very close above. (C) 1995 John Wil ey & Sons, Inc.