AB-INITIO STUDY OF THE ELECTRONIC-SPECTRUM OF C2H2- I - VERTICAL SPECTRUM AND ANGULAR POTENTIAL CURVES( )

Results of ab initio MRD-CI calculations of the vertical spectrum and trans-bending, cis-bending and torsional potential energy curves for l ow-lying doublet electronic states of the acetylene cation are present ed. At the linear nuclear geometry these states correlate with X (2)Pi (u), 1 (2)Sigma(g)(+), 1 (2)Pi(g), 1 (2)Phi(g), 1 (2)Sigma(u)(+), and 2 (2)Pi(g), all of them being of predominantly valence character. (C) 1998 Elsevier Science B.V. All rights reserved.