THE $3\nu_{2}$ OVERTONE BAND OF $H_{3}^{+}$
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Date
1993
Journal Title
Journal ISSN
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Publisher
Ohio State University
Abstract
Because of the small mass of hydrogen and the relatively shallow vibrational potential, the transition probabilities of overtone bands of $H_{3}^{+}$ do not decrease as drastically as those of other molecules. According to the first principle calculation by Dinelli, Miller, and $Tennyson^{1}$, the spontaneous emission probability of the second overtone band $3\nu_{2} (\ell = 1) \rightarrow 0$ is smaller than that of the fundamental band by a factor of less than 10. This corresponds to the reduction of absorption coefficient of about 180 and the spectrum is observable at the $H_{3}^{+}$ ion concentration of $3 \times 10^{10} cm^{-3}$. We have observed 15 vibration rotation transitions from 7265.9 to $6806 cm^{-1}$. InGaAsP diode lasers were used in a short-external cavity configuration to achieve laser operation in a single longitudinal mode. The observed frequencies agree with earlier prediction by Miller and Tennyson within $3 cm^{-1}$ but agree better with their new $prediction^{2}$.
Description
$^{1}$. B.M. Dinelli, S. Miller, and J. Tennyson, J. Mol. Spectrose. 153, 718-725(1992) $^{2}$. B.M. Dinelli, private communication.
Author Institution: Department of Engineering Physics, McMaster University; Department of Chemistry and Department of Astronomy and Astrophysics., The University of Chicago
Author Institution: Department of Engineering Physics, McMaster University; Department of Chemistry and Department of Astronomy and Astrophysics., The University of Chicago