Spin?orbit ab initio curves of 80 Se2+ ion and the assignment of photoelectron spectra of 80 Se2 molecule

This paper carries out ab initio calculations to study the 80 Se2(X3?g-) state and 80 Se2+(X2 IIg), 80 Se2+(a4 IIg) states by using completed active space self-consistent field and multi-reference second order perturbation theory. The electronic curves of these states including spin?orbit coupling are calculated, and then the spectroscopic parameters are obtained. The photoelectron spectra of 80 Se2 molecule in gas phase are assigned according to Franck?Condon analysis based on calculated potential energy curves. The ionization energies of 80 Se2 molecule are determined by the present calculation.