Vibronic structure of the CO₂⁺ion: reinvestigation of the antisymmetric stretch vibration in the [Xtilde], Ã, and [Btilde] states

We review the literature regarding v 3 excitation in the CO2 + ion and present a consistent scheme of vibronic assignments involving v 3 and 2v 3 in the A2Πu-[Xtilde]2Πg and [Btilde]2Σu +-[Xtilde]2Πg bands. A key new piece of information enabling this reanalysis is provided by LIF detection of several A(ν102)2Πu-[Xtilde](000)2Πg absorption bands which are not observed in emission spectroscopy. We combine this information with previous measurements of the A(ν101)2Πg-[Xtilde](001)2Πu bands and infrared work on the [Xtilde](001)2Πu-[Xtilde](000)2Πg transition to determine the A(ν10ν3)2Π level structure. We also carry out a rotational analysis of the A(202)2Πu-[Xtilde](000)2Πg band and identify a number of previously misassigned bands as arising from A(ν100)2Πu-[Xtilde](ν102)2Πg transitions. Precise molecular constants for the [Xtilde](002)2Πg level are obtained from a recent A(000)2Πu-[Xtilde](002)2Πg emission spectrum recorded using a Fourier transform spectrometer. Finally, identification of the [Btilde](0...