Configuration interaction study of the electronic spectrum of SnSe+

The electronic spectrum of SnSe+ has been studied from the ab initio based multireference configuration interaction calculations which include relativistic effective core potentials of both the atoms. Potential energy curves of all 12 low-lying states, which dissociate into the lowest asymptote Sn+(2Pu) + Se(3Pg), have been constructed. The ground-state dissociation energy is estimated to be 2.74 eV. Spectroscopic constants of eight low-lying states of SnSe+ within 25 000 cm−1 of energy are computed. The electronic states, which include the spin–orbit coupling, have also been investigated. The ground-state spin–orbit splitting is about 1840 cm−1. The radiative lifetimes of B2Σ+, A2Σ+, and 22Π states of SnSe+ are calculated. The effect of the spin–orbit coupling on the A2Σ+–X2Π transition has been studied in details. The electric dipole moments of the ion in the low-lying states are reported. The vertical ionization energy of the ground-state SnSe is about 8.93 eV.