AB-INITIO CONFIGURATION-INTERACTION STUDY OF THE ELECTRONIC-SPECTRUM OF SIH+

Ab initio configuration interaction calculations have been carried out for SiH+ using a large Gaussian basis set. Calculated spectroscopic c onstants of the X(1) Sigma(+) and A(1) Pi states as well as the excita tion energy and the f(00) value of the A(1) Pi --> X(1) Sigma(+) trans ition and the lifetime tau(0) of the A(1) Pi state are obtained in goo d agreement with experiment. In addition, the energies of the various asymptotes (up to 13 eV above the X(1) Sigma(+) minimum) computed for large internuclear separations are found to agree with observed atomic values to within 0.3 eV in each case. Spectroscopic constants, excita tion energy, lifetime and other quantities are predicted for a large n umber of higher excited states. Many other bound states have been indi cated in the present calculations and their computed spectroscopic con stants should provide a basis for further experimental investigations of the spectrum of this ion. Special emphasis is placed on the long-ra nge characteristics of the SiH+ potential curves on the way to their r espective atomic asymptotes.