Ab initio configuration interaction study of the electronic spectrum of SiH+

Ab initio configurationi nteraction calculations have been carried out for SiH+ using a large Gaussian basis set. Calculated spectroscopic constants of the X 1Σ+ and A 1Π states as well as the excitation energy and the tf00 value of the A 1Π → X 1Σ+ transition and the lifetime τ0 of the A 1Π state are obtained in good agreement with experiment. In addition, the energies of the various asymptotes (up to 13 eV above the X 1Σ+ minimum) computed for large internuclear separations are found to agree with observed atomic values to within 0.3 eV in each case. Spectroscopic constants, excitation energy, lifetime and other quantities are predicted for a large number of higher excited states. Many other bound states have been indicated in the present calculations and their computed spectroscopic constants should provide a basis for further experimental investigations of the spectrum of this ion. Special emphasis is placed on the long-range characteristics of the SiH+ potential curves on the way to their respective atomic asymptotes.