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# OBSERVATION OF FORBIDDEN TRANSITIONS OF $H_{3}^{+}$

Please use this identifier to cite or link to this item: http://hdl.handle.net/1811/12493

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 Title: OBSERVATION OF FORBIDDEN TRANSITIONS OF $H_{3}^{+}$ Creators: Xu, L. W.; Rosslein, M.; Gabrys, C. M.; Oka, T. Issue Date: 1991 Abstract: Due to the large anharmonicity and vibration-rotation interactions in the $H_{3}^{+},$ the IR forbidden transitions $v_{1} + v_{2} \leftarrow v_{2}$ and $v_{1}\leftarrow$ 0 can borrow intensity from the allowed $2 v_{2} (1=2) \leftarrow v_{2}$ and $v_{2}\leftarrow 0$ bands. Using the ab initio $calculation^{1}$ as a guide, we searched for these transitions using the difference frequency laser system in the region from 2840 $cm-^{1}$ to 3280 $cm^{-1}$. $H_{3}^{+}$ was produced in a liquid nitrogen cooled AC glow discharge of $H_{2}$ and He mixtures. About 170 new lines have been observed, and the analysis is under way. Up to now, 12 lines have been assigned to the band $v_{1} + v_{2}\leftarrow v_{2}$; and 2 lines to $v_{1}\leftarrow 0$. During this process, we have also assigned many new transitions for the other bands. The forbidden transitions of $H_{3}^{+}$ is of special interest for astrophysics since it is an important mechanism to cool down the excited $H_{3}^{+}$ in the space. It also gives absolute rovibrational energy values for the $v_{1}$ and the $v_{1} + v_{2}$ states. URI: http://hdl.handle.net/1811/12493 Other Identifiers: 1991-TA-8