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

Three-dimensional potential-energy functions for the X 2A1 and A 2B1 s tates of SiH2+ have been derived from extensive ab initio multi-refere nce configuration interaction (MRCI) calculations. Spectroscopic const ants have been derived from the potential-energy functions by second-o rder perturbation theory. The calculated values are in very good agree ment with the experimental data and also provide a secure value for th e A(o) rotational constant for the X 2A1 state. Rovibronic levels were calculated by a variational method which takes into account Renner-Te ller coupling. Theoretically derived transition wavenumbers are in goo d agreement with experimental results.