Knowledge Bank

We report our recent observation of the first overtone band $[2\nu 2(l=2)\leftarrow 0]$ of $D3+$ in the $3-\mu m$ region using a difference frequency laser spectrometer combined with a hollow cathode discharge device and concentration modulation. This band gains appreciable intensity as a result of high anharmonicity of the potential. A total of over 100 lines have been observed. The observed frequencies agree well (within $0.05cm-1)$ with first principles $calculations1$ based on the ab initio potential of Meyer. Botschwina, and $Burton2$ with adjusted parameters. This observation provides information on the assignment of the laboratory FTIR emission spectrum of a vibrationally and rotationally hot deutenum $plasma3$ produced in a hollow cathode by Majewski, McKellar, and Watson.