A correlation study of boron dimers and trimers

We have carried out ab initio molecular orbital studies of neutral and charged boron dimers and trimers, using a large basis set. Electron correlation effects are included through the techniques of fourth order many body perturbation theory. Results for total energies, geometries, binding energies, and binary fragmentation energies are presented, and where possible compared with published results. Stabilities of the geometries considered are further studied through a vibrational-mode analysis. The ground state of B₂ is predicted to be a triplet; of B ₂ ^? , a quartet, and of B ₂ ⁺ a doublet. The ground state of B₃ is a triangular doublet, of B ₃ ^? a linear singlet and of B ₃ ⁺ a triangular singlet.