THEORETICAL POTENTIAL-ENERGY FUNCTIONS AND THE ROVIBRONIC SPECTRUM OF THE SIH2+ ION

Three-dimensional potential-energy functions for the X 2A1 and A 2B1 states of SiH2+ have been derived from extensive ab initio multi-reference configuration interaction (MRCI) calculations. Spectroscopic constants have been derived from the potential-energy functions by second-order perturbation theory. The calculated values are in very good agreement with the experimental data and also provide a secure value for the A(o) rotational constant for the X 2A1 state. Rovibronic levels were calculated by a variational method which takes into account Renner-Teller coupling. Theoretically derived transition wavenumbers are in good agreement with experimental results.