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High resolution laser spectroscopy of the C2Δ-X2Σ+ transition of CaOH and CaOD: Vibronic coupling and the Renner-Teller effect

The products of vaporization of boron/carbon mixtures around 3000 K were trapped in argon matrices at 10 K and their Fourier transform infrared spectra were measured. Analysis of the spectra combined with the predictions of density functional theory (DFT) calculations have resulted in the assignment of a previously observed vibration at 1194.4 cm−1 to the ν2 fundamental of cyclic BC2, which is effectively symmetric. The assignment is supported by 10B, 11B, and 13C isotopic data and is in good agreement with the theoretical predictions.

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Results of experiments on lithium doped rare gas solids (Ar, Kr, and Xe) prepared by laser ablation of solid lithium are presented, including near UV–visible absorption spectra, and photobleaching and annealing studies of the matrices, as well as visible emission spectra of the laser ablated Li plume. The UV–visible absorption spectra of Li/Ar and Li/Kr matrices generated by cocondensing the rare gas and laser ablated Li atoms at 12 K are dominated by a ‘‘blue-shifted triplet’’ absorption not observed in previously published studies. Control experiments on Li/Ar and Li/Kr matrices generated using a Knudsen oven as the Li atom source showed exclusively an ‘‘unshifted triplet’’ absorption, in agreement with previous studies. The new absorption features are attributed to Li atoms trapped in novel sites in the Ar and Kr solids; sites not accessible to Li atoms generated by the conventional Knudsen effusion technique. Spectra of Li/Xe samples prepared by the laser ablation method showed exclusively the unshifted triplet absorption pattern, in agreement with previous Knudsen effusion studies. All of these observations are explained by a simple model which compares the sizes of the various trapping sites in the rare gas solids to the collision diameters obtained from the Li atom–rare gas atom pair potentials.