The molecular structure and a Renner-Teller analysis of the ground and first excited electronic states of the jet-cooled CS2+ molecular ion

The A (2)Pi(u)-X (2)Pi(g) electronic band system of the jet-cooled CS2+ ion has been studied by laser-induced fluorescence and wavelength-resolved emission techniques. The ions were produced in a pulsed electric discharge jet using a precursor mixture of carbon disulfide vapor in high-pressure argon. Rotational analysis of the high-resolution spectrum of the (2)Pi(3/2) component of the 0(0)(0) band gave linear-molecule molecular structures of r(0)(')=1.5554(10) A and r(0)(')=1.6172(12) A. Renner-Teller analyses of the vibronic structure in the spectra showed that the ground-state spin-orbit splitting (A=-447.0 cm(-1)) is much larger than that of the excited state (A=-177.5 cm(-1)), but that the Renner-Teller parameters are of similar magnitude and that a strong nu(1)-2 nu(2) Fermi resonance occurs in both states. Previous analyses of the vibronic structure in the ground and excited states of the ion from pulsed field-ionization-photoelectron data are shown to be substantially correct.