Ab initio study of the electronic spectrum of C<inf>2</inf>H<inf>2</inf>⁺. : I. Vertical spectrum and angular potential curves

Abstract

Results of ab initio MRD-CI calculations of the vertical spectrum and trans-bending, cis-bending and torsional potential energy curves for low-lying doublet electronic states of the acetylene cation are presented. At the linear nuclear geometry these states correlate with X 2Πu, 1 2Σ+g, 1 2Πg, 1 2Φg, 1 2Σ+u, and 2 2Πg, all of them being of predominantly valence character.