Spectroscopy and relaxation of CS2+ in solid Ne

Absorption and laser induced fluorescence spectra of CS2+ in solid Ne are re-examined. Isotopic studies with 13CS2 confirm that most of the strong vibronic bands of the ? 2Πg→? 2Πu transition are due to an almost perfect mixture of ν1 and ν2 modes. Extension of the spectrum into the UV leads to identification of the overtone of the third vibrational mode, 2ν′3=3288 cm−1, whose frequency increases considerably in the upper state. The origin of the X 2Πg→? 2Σu+ transition is also observed. ? 2Σu+ state excitation results in efficient nonradiative transition into the ? 2Πu state. Study of spectral line shapes associated with the ? 2Πg→? 2Πu transition suggests inefficient energy transfer between ν3 and the lower frequency modes.