ROTATIONAL AND VIBRATIONAL CONSTANTS OF SEVERAL LOW-LYING LEVELS OF NCO FROM 4658 {\AA} PUMPED LEF
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Date
1984
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Publisher
Ohio State University
Abstract
Previously, we have reported the laser excited fluorescence spectrum of NCO in an atmospheric pressure flame using argon laser $excitation.^{1}$ This paper reports a further investigation of the fluorescence from the most interesting of the pump lines, the 4658 {\AA} pump line. The fluorescence is obtained, as before, by placing an atmospheric pressure $CH_{4}/N_{2}O$ flame in the extended cavity of an $Ar^{+}$ ion laser. The resulting fluorescence in the $A^{2}\Sigma^{+}\leftarrow X^{2} \pi$ system of NCO is dispersed using a lm monochromator and detected with a vidicon (OMA I). The fluorescence spectrum reveals that the laser pumped rovibronic level, the $(0,0^{0},0) F_{2}31$, is much more highly populated than any other level. Emissions from this level to the $(0,0^{1},0), (1,0^{1},0), (0,0^{1},1)$ and $(0,1^{0},0)$ levels have been observed. Rotational analyses have been performed on the emissions from the pumped rovibronic level to the first three of the above ground state vibrational levels. The frequencies of the two stretching vibrations and the $A_{v}$ and $B_{v}$ spin-orbit and rotational constants have been obtained. The results are in excellent agreement with those from a concurrent $study.^{2}$ In addition, our previous tentative assignment of the pumping transition as $Q_{2}31$ in the $(0,0^{0},0)\leftarrow (1,0^{1},0)$ band has been confirmed.
Description
$^{\ast}$ NAS-NRC POSTDOCTORAL RESEARCH ASSOCIATE 1. W.R. Anderson, J.A. Vanderhoff, A.J. Kotlar, M.A. DeWilde and R.A. Beyer, J. Chem. Phys. 77, 1677 (1982). 2a. R.A. Copeland, D.R. Crosley, and G.P. Smith, submitted to the 20th Symp. (Int.) on Combustion, Ann Arbor, Mich., August 1984. b. D.R. Crosley, private communication.
Author Institution: Ballistic Research Laboratory
Author Institution: Ballistic Research Laboratory