Knowledge Bank

The $\nu 2$ fundamental band of $D3+$ was first observed in 1980 by Shy, Farley, Lamb, and $Wing,1$ and later studied in detail by Watson, Foster, and $McKellar,2$ who used a tunable diode laser spectrometer and a large cooled hollow cathode cell with an absorption path of 11 m. Their analysis covered the region from 1670 to $2170cm-1$, and included J-values up to 8. The present work is an extension of this earlier analysis to cover a wider wavenumber range and higher J-values. We use small, high current density, hollow-cathode $cells3$ with water cooling in order to record both emission $spectra,4$ with a Bomem FT spectrometer, and absorption spectra, with a diode laser spectrometer. So far, we have assigned a number of new transitions in the R-branch from $2100-2300cm-1$, with J-values of up to 12. For J-values greater than about 7 in the excited $v2=1$ state, Coriolis interactions with the $v1=1$ state start to become significant for certain levels. These perturbations make it more difficult to locate and assign the affected transitions, but they also offer the possibility of gaining direct experimental information about the infrared forbidden $v1$ vibration.