INFRARED SPECTRUM OF THE $\nu_{3}$ BAND OF $NH_{3}^{+}$
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Date
1987
Journal Title
Journal ISSN
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Publisher
Ohio State University
Abstract
We have observed the vibration-rotation spectrum of the $\nu_{3}$ band of $NH_{3}^{+}$. The ion was produced in an air-cooled discharge cell with a gas mixture He: $H_{2}: NH_{3} (600:15:2)$ and with a total pressure of $\approx 6 Torr$. The spectrum was observed using a difference frequency laser system combined with velocity modulation. About 100 lines have been measured and assigned. Spin-rotation splittings for most Q-branch lines were well resolved. A symmetric rotor Hamiltonian with $\ell$-resonance and $A_{1} - A_{2}$ splitting was used to analyze the spectrum. We find that $NH_{3}^{+}$, like the isoelectronic radical $CH_{3}{^{1,2}}$ is a planar molecule with $D_{3b}$ symmetry and with an $^{2}A_{2}^{\prime\prime}$ electronic ground state. We obtain the following preliminary vibration-rotation constants (in $cm^{-1}$):[FIGURE]
Description
Numbers in parentheses are $3\sigma$. $^{1}$ G. Herzberg, Proc. Roy. Soc. 262A, 291 (1961). $^{2}$ C. Yamada, E. Hirota, K. Kawaguchi, J. Chem. Phys. 75, 5256 (1981).
Author Institution: Department of Chemistry and Department of Astronomy and Astrophysics, The University of Chicago; Istituto di Spettroscopia Molecolare del, C. N. R.
Author Institution: Department of Chemistry and Department of Astronomy and Astrophysics, The University of Chicago; Istituto di Spettroscopia Molecolare del, C. N. R.