Multireference configuration interaction study of the low-lying electronic states of SiS+

The electronic spectrum of (SiS+)-Si-28-S-32 has been studied by using relativistic configuration interaction calculations which include effective core potentials. Spectroscopic constants and potential energy curves of low-lying states within 5 eV have been computed. The spin-orbit coupling has also been included in the calculations. The vertical ionization potentials of the ground-state SiS to the ground and a few excited states of SiS+ have been calculated and compared with the experimentally derived values. The transition moment functions of some dipole allowed transitions such as B(2)Sigma(+)-X(2)Pi, B(2)Sigma(+)-A(2)Sigma(+) etc have been constructed. The dipole moments of three doublets such as X(2)Pi, A(2)Sigma(+) and B(2)Sigma(+) and three quartets such as (4)Pi, 4Sigma(+) and (4)Delta of SiS+ are reported. The radiative lifetimes of a couple of excited (2)Sigma(+) states are estimated.