Configuration interaction study of the electronic states and spectroscopic properties of selenium monoxide.

The electronic spectrum of the selenium monoxide (SeO) molecule has been studied theoretically by using ab initio based multireference singles and doubles configuration interaction (MRDCI) methodology, which includes relativistic effective core potentials (RECP) and suitable Gaussian basis sets of the atoms. Potential energy curves of several electronic states correlating with the lowest and second dissociation limit are constructed. Spectroscopic parameters, namely Te, re, and ωe of 10 bound Λ-S states of the molecule within 4.71 eV are estimated and compared with the available data. In addition, binding energies of the ground and some excited states are computed. The changes in the potential energy curves and spectroscopic properties after the inclusion of the spin-orbit coupling are discussed and also compared with the available data. Transition probabilities of some dipole-allowed and spin forbidden transitions are estimated and radiative lifetimes of some excited states are reported. Dipole moments of some low-lying Λ-S states as a function of bond distance have also been computed.