Theoretical study of the low-energy BiN spectrum

The ground X0+(1Σ+) and the Three lowest a11, a20−(3Σ+) and b1o+ (5Σ+) excited states of the BiN molecule have been calculated employing the relativistic CI method based on effective core potentials. The calculated spectroscopic constants (Te, re, and ωe) are in good agreement with experimental results, as also is the ground state De value computed to be 28400 cm−1. The a20− state is predicted to lie 1740 cm−1 higher than a11. It is shown that the b10+ state has a strongly perturbed potential curve with a shoulder on its repulsive limb due to an avoided crossing between the 5Σ+ and 3Π states. This result explains the increase in its Bv′ constant v′ found experimentally. The radiative lifetimes have also been calculated for all electric-dipole-allowed transitions between the states considered.