Accurate ab initio calculations of the ground states of FeC, FeC+, and FeC−

Abstract

For the ground states of the diatomic carbide FeC(X (3)Delta) and its ions, FeC(+)(X (2)Delta) and FeC(-)(X (2)Delta), we report on accurate multireference variational ab initio results employing augmented correlation consistent basis sets of quintuple cardinality. The dissociation energies and bond lengths are found to be D(0) (0)=87+/-1, 95.2, and 84+/-1 kcal/mol at r(e)=1.581, 1.556, and 1.660 A for FeC, FeC(+), and FeC(-), respectively. All our final numbers are in agreement with the available experimental data.