Ab initio study of the electronic structure of manganese carbide

We report electronic structure calculations on 13 states of the experimentally unknown manganese carbide (MnC) using standard multireference configuration interaction (MRCI) methods coupled with high quality basis sets. For all states considered we have constructed full potential energy curves and calculated zero point energies. The X state, correlating to ground state atoms, is of (4)Sigma(-) symmetry featuring three bonds, with a recommended dissociation energy of D-0=70.0 kcal/mol and r(e)=1.640 angstrom. The first and second excited states, which also correlate to ground state atoms, are of (6)Sigma(-) and (8)Sigma(-) symmetry, respectively, and lie 17.7 and 28.2 kcal/mol above the X state at the MRCI level of theory. (c) 2006 American Institute of Physics.