Theoretical potential-energy functions and the rovibronic spectrum of the SiH +2 Ion

Abstract

Three-dimensional potential-energy functions for the X²A₁ and òB₁ states of SiH⁺₂ 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 X²A₁ 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.