The laser spectroscopy of cool, cold, and very cold molecular ions

摘要: Molecular ions have long presented a challenge to spectroscopists. Because of the extreme difficulty in generating molecular high concentrations, sensitivity limitations restricted work this field. The technique laser-induced fluorescence (l.i.f.) has provided us with means partially overcome limitation. L.i.f. spectra small ions, e.g. N 2 +, CO+ and CO show Doppler-limited resolution. Besides their spectroscopic information content, such also serve as quantum-state selective ion detectors, by which dynamical processes involving can be followed. been recorded for larger organic olefinic, acetylenic benzenoid cations. large ions’ spectral congestion, caused number levels populated at room or elevated temperatures, severely limit resolution interpretability spectra. As surmounting problem, we studied many cations reduced temperatures. techniques employed include liquid free jet expansion cooling gas phase, isolation solid Ne matrices. combination these different lead wealth about electronic structure, vibrational frequencies, Jahn-Teller effects, etc., ions.