The Spectroscopy of Molecular Ions.

Available from UMI in association with The British Library. Requires signed TDF. Photodissociation spectra for HD^ {+}, H_sp{2} {+} and D_sp{2} {+} are measured at four different frequencies in the infrared. Vibration-rotation transitions of HD^ {+} have been measured in the 21-17 and 22-17 bands. Nuclear hyperfine structure was resolved, and analysis yielded values of the proton and deuteron Fermi contact parameters; consideration of these Fermi contact parameters shows that at levels close to its first dissociation limit (H^{+} + D) HD^{+} is best described as a proton loosely interacting with a deuterium atom. A method of preparing highly rotationally excited HD^{+} is described, and preliminary measurements up to R(11) of the 17-15 band of HD^{+} are reported. A bound to rotationally-quasibound transition (16,17-13,18) is measured, showing that the quasibound state, which correlates with the lowest dissociation limit (H^{+ } + D), predissociates exclusively to protons. Saturation effects leading to reversed phase lineshapes are noted. The technique of laser excitation and electric field dissociation spectroscopy is used to measure electronic spectra of D_sp{2}{+} between high vibration-rotation levels in the ground (^2Sigma_{rm g} ) electronic state and vibration-rotation levels of the van der Waals minimum in the first excited ( ^2Sigma_{rm u}) electronic state. Preliminary measurements of the photo-predissociation spectrum of H_sp{3}{+} and its deuterium isotopes are described, confirming recent theoretical predictions.