Ab initio calculations of A′ and A″ states of nitrosyl cyanide

Abstract

Single-Configuration RHF (Restricted–Hartree–Fock) calculations have been made with a double-zeta basis of several low-lying states of ONCN of both A′ and A″ symmetry and for five of these the optimum geometry has been determined. However, to obtain approximate agreement with observed spectra and a compatible ordering of states, multiple-configuration calculations of the lowest ¹A′, ³A″ and ¹A″ states have been made by the Generalized Valence Bond (GVB) method.