A study of the spark spectra of Indium

The spectra of Indium have been photographed from the infra-red to the vacuum ultra-violet on a two metre vacuum spectrograph, a twenty-one foot grating, and a Littrow prism spectrograph. Two sources have been used: an electrodeless discharge and a condensed vacuum spark. Some 1250 Indium lines have been measured in the region 8200 to 237 Angstroms. Oh the basis of these measurements, new energy levels have been found for all spark spectra up to In V. The main extension of analysis has been in In III where we have added thirty-five new terms. The resulting analyses have been critically examined in terms of intermediate coupling theory, which is shown to be satisfactory when perturbations are not present, except in one configuration in In IV in which there are serious departures from theory. Hyperfine structure has been measured in In III and In II, and perturbation calculations have been made which account for observed departures from the Landé interval rule.Science, Faculty ofPhysics and Astronomy, Department ofGraduat