Carbonyl Boron and Related Systems: An ab Initio Study of B−X and YB⋮BY (1Σg+), Where X = He, Ne, Ar, Kr, CO, CS, N2 and Y = Ar, Kr, CO, CS, N2

Using the coupled-cluster methodology and large correlation consistent basis sets, we have examined the BX and YBBY ( 1 Σ g + ) molecules, where X = He, Ne, Ar, Kr, CO, CS, and N 2 and Y = Ar, Kr, CO, CS, and N 2 . For the B−X series we have constructed full potential energy curves reporting total energies, equilibrium geometries, binding energies, and also spectroscopic constants for the diatomic sequence. The B−CO, B−CS, and B−N 2 ground states are of 4 Σ - and 2 Π symmetries, respectively, with the 4 Σ - states having remarkably strong binding energies with respect to their adiabatic fragments. For all the triatomics the first excited 4 P state of B plays an instrumental role in the binding process, while the bonding mechanism in either the 2 Π or 4 Σ - symmetries is due to charge transfer to the empty 2p z orbital of the B atom. The YBBY series results by singlet coupling two B−Y 4 Σ - moieties, leading to acetylene-like YB⋮BY systems of 1 Σ g + symmetry.