Electronic spectrum of SiSe+: a MRDCI study

Multireference configuration interaction calculations have been carried out to study hitherto unknown electronic structure and spectroscopic properties of the low-lying electronic states of SiSe+. Potential energy curves of 16 Λ–S states of the ion are reported while the spectroscopic constants of 13 states are estimated. The X2Π, A2Σ+, B2Σ+, and 32Σ+ states of SiSe+ are identified as important ones for the spectroscopic measurement. The vertical ionization energies of the ground-state SiSe to the ground and a few low-lying excited ionic states have been computed. Transition probabilities of B2Σ+–X2Π, 32Σ+–X2Π, and B2Σ+–A2Σ+ transitions are calculated from the MRDCI energies and wave functions. The ground-state spin–orbit splitting is estimated and the radiative lifetimes for the X22Π1/2–X12Π3/2 and A 2 Σ 1 / 2 + - X 1 2 Π 3 / 2 transitions are reported. The electric dipole moment functions of the ground and some low-lying excited states of SiSe+ are computed.