VIBRONIC SPECTRUM OF THE CS-2(+) ION IN THE X 2-PI-G STATE

Based on ab initio electronic structure calculations, the three-dimensional potential energy functions for the X2PI(g) Renner-Teller system of CS2+ have been generated and used in variational beyond Born-Oppenheimer calculations of the rovibronic energy levels. All vibronic levels (J=P) for energies up to 2500 cm-1 are given for K=0-3. Available experimental data agree to within 10 cm-1 with the theoretical results. From the compositions of the rovibronic wavefunctions new assignments are made for levels within the Fermi polyads 2nu1 + nu2 = 2, 4, and 6. The positions of many so far unknown energy levels are predicted.