Ground and excited states of BF3+. Coupled cluster and density functional studies

Abstract

Ab initio (CCSD, CCSD(T), EOM-CCSD, MRCI) and DFT calculations were performed on BF3+. Ab initio methods predict a double well potential with two C2v minima (2B2) and a D3h transition state (2A2′). The minimum with two short and one long B–F distances (2S1L) is lower in energy than 1S2L by 0.10eV (CCSD(T)). DFT methods with common hybrid functionals only find 1S2L. Long-range corrected functionals are needed for the other C2v state. Excited 2B2 states which vibronically interact with the ground state have minima close to D3h symmetry. The double well potential is caused by strong pseudo Jahn–Teller coupling, due in part to very low excitation energies. Vibrational frequencies, vertical excitation energies, hyperfine coupling constants and g-factors are presented for both C2v isomers.