The infrared spectroscopy of the products of ion–molecule reactions trapped in the solid rare gases

Studies of the infrared spectra of small molecular ions offer valuable information regarding the structures and chemical bonding properties of these species. Suitable concentrations of ions for such studies can be obtained by trapping them in dilute solution in a rare-gas solid. The characteristics of infrared absorptions of species trapped in the various rare gases are surveyed, as are factors important in ion production and identification. Emphasis is given to the development and application of a modified discharge configuration which has permitted the identification of many small molecular cations and anions. This configuration is now also being used for studies of the infrared spectra of primary products of some ion–molecule reactions.