Richard A. Kennedy

Infrared predissociation spectrum of the H+3 ion

We have observed an infrared spectrum of the H+3 ion containing nearly 27u2009000 lines which span only 222 cm−1 from 872 to 1094 cm−1. A beam of H+3 ions at a potential of from 1.2 to 10.5 kV is aligned to be collinear with an infrared laser beam from a carbon dioxide cw laser. Photodissociation occurs to produce fragment H+ ions which are separated from the parent H+3 ions using an electrostatic analyzer. Doppler tuning is accomplished by scanning the H+3 ion beam potential and resonance lines corresponding to an increase in fragment H+ ion current are detected by means of a velocity modulation technique. The observed linewidths range from 3 to 60 MHz, with additional broader lines also being detected by chopping the laser beam. We believe that each resonance line arises from predissociation of H+3 to form H2 and H+. Pseudo‐low resolution spectra constructed by computer convolution of the experimental data show well defined peaks which correspond closely in transition frequency to j=3–5 rotational transitio...

Infrared bound to quasibound vibration-rotation spectrum of HeH+ and its isotopes

Abstract The positions and widths of all the bound and rotationally quasibound levels of the ground states of 4 HeH - , 4 HeD′- 3 HeH - and 3 HeD′ have been calculated using an adiabatic potential. From these theoretical data the positions of bound to quasibound vibration-rotation transitions lying in the range of the carbon dioxide laser 0880 to 1090 cm 1 have been predicted. Infrared predissociation spectroscopy of Doppler-tuned ion beams has been used to determine the positions and widths of many of the resonances. There is excellent agreement between the theoretical predictions and the experimental measurements.

Vibration-rotation spectroscopy of the HD+ion near the dissociation limit: Part VI. Nuclear hyperfine interactions

Reexamen et mesure de la bande 22-17 dans HD + a proximite de la limite de dissociation a laide dune technique experimentale amelioree. Analyse des spectres radiofrequence et double resonance IR. Comparaison avec les calculs theoriques

Vibration-rotation spectroscopy of the HD+ ion

An approach to the spectroscopy of molecular ions which has obvious appeal is to use the well-established technique of mass spectrometry for producing an appropriate mass-selected ion beam, and to allow the ion beam to interact with electromagnetic radiation. One soon concludes, however, that the direct detection of the absorption of radiation will be difficult, and probably impossible. The reason is that even an intense molecular ion beam (e.g., 1012 ions/sec) has a very low ion density. Consequently, the successful approaches to date have involved indirect detection of absorption spectra; the basic principle is that one attempts to detect the changes in internal state of the ion, brought about by the absorption of radiation, through changes in either the parent ion beam intensity or secondary ion intensities [1]. In the case of the HD+ ion two successful approaches have been described, one involving charge-exchange reaction with H2, the other involving photodissociation. These experiments are described in detail in the third and fourth sections of this review.