RO-VIBRONIC STATES IN THE ELECTRONIC GROUND-STATE OF CO2+(X2-PI-G)

From the adiabatic three-dimensional potential energy functions of the Renner-Teller components for the electronic ground state X(2)II(g) of CO2+ the ro-vibronic levels have been calculated by a variational approach considering full dimensionality, anharmonicity, rotation-vibration, electronic angular momenta, and electron spin coupling effects. The calculated ro-vibronic levels for J = P agree to within about 10 cm-1 with the experimental data for energies up to 4300 cm-1 and the set of these term values up to 2J = 9 is given. The electron-nuclear motion and anharmonicity coupling effects have been investigated by an analysis of the composition of the ro-vibronic variational eigenfunctions. Due to the anharmonic couplings the vibronic levels can be grouped in blocks of Fermi polyads. This finding considerably facilitates the assignments of the highly excited ro-vibronic states in the electronic ground state of CO2+.