Electronic Structure and Chemical Bonding of MoX Molecules, where X = Li, Be, B, C, N, O, and F

In the present work, the ground state as well as some excited states of the MoX diatomic molecules, where X = Li, Be, B, C, N, O, and F, have been investigated to shed light on the nature of their chemical bonding. To this end, density functional theory, multireference configuration interaction and coupled-cluster methodologies have been employed in conjunction with aug-cc-pV5Z-(-PP) and aug-cc-pwCV5Z-(-PP) basis sets. Dissociation energies, dipole moments, and various spectroscopic constants are calculated with a view to studying the impact of the gradual increase of the number of valence electrons of X atom moving across the second period of the periodic table on the calculated properties of MoX. The Mo atom is a versatile atom forming different types of chemical bonds. The bonds formed in MoX range from a half bond (MoBe) to a quadruple bond (MoC), while all types of bonds are observed, including dative, covalent, and ionic. The corresponding dissociation energies range from 14.4 to 149.2 (152.5; CBS limit) kcal/mol at the C-MRCISD+Q and C-RCCSD-(T)/aug-cc-pV5Z-(-PP) levels. Finally, to evaluate the bond strength of the ground states, it was found that the dissociation energy per bond value is ∼ 25 kcal/mol for MoLi, MoBe and MoB, ∼ 40 kcal/mol for MoC and MoN, 61 kcal/mol for MoO and 111 kcal/mol for MoF which forms an ionic bond.