关键词: B₂, SOCI, 激发态

Abstract: The optimized geometries of several low-lying electronic states of B₂ are obtained by using an energy gradient technique and SCFor SOCIenergy minimization methods with a standard 6-31G^* basis set.In the upper states of B₂, an increase in bond strength can occur in case of one and two-excitations from the σ_n antibonding MOinto either a bonding σ_q orπ_n MO, and the bonding effect of π_n, is superior to that of σ_a,.The transition energies(ET) are given at an accurate second order configuration interaction (SOCI) level of theory, and based on the close agreement between the calculated and observed ET, the Douglas-Herzberg transition is assigned by transition from C³∑_M^- to the ground state X³∑_M^-.In addition, we have obtained the vibrational frequencies(ω_e) for the ground and excited states with the model potential function method.

Key words: B₂, SOCI, Excited states