ANALYSIS OF THE 5800 \AA SCHUSTER BAND OF THE $ND_{4}$ RADICAL
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Date
1982
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Ohio State University
Abstract
An emission system first observed over a hundred years ago by Schuster in various DC discharges in flowing $NH_{3}$ has been restudied at the NRC in Ottawa, where mixed isotopic spectra using both D and $^{15}N$ allowed the carrier of the spectrum to be positively $identified^{1}$ as $NH_{4}$. The results of ab initio $calculations^{2}$ and a preliminary rotational $analysis^{1}$ led to a provisional assignment of one hand as a $(3d)^{2}F_{2} - (3s)^{2}A_{1}$ Rydberg transition, even though such a transition would be parity forbidden in the united atom limit. The present work attempts to place the original rotational analysis on a more quantitative basis. A computer program at l'Universite de Dijon, France, originally $developed^{3}$ for vibrational transitions in tatrahedral molecules, was used to carry out a least squares fit of the rotational structure of the observed electronic transition in $NH_{4}$. Group theoretical arguments alone permit the Dijon rotation-vibration Hamiltonian to be used as a phenomenological rotation-electronic Hamiltonian. However, while the precise meaning of the various scalar and tensor operators in the Dijon $formalism^{3}$ is well understood for the rotation-vibration problem in $CH_{4}$, the significance of these parameters for the rotation-electronic problem in $NH_{4}$ has yet to be determined. Various theoretical points and the status of the least squares fit will be discussed.
Description
$^{1}$ G. Herzberg, Faraday Disc. Chem. Soc. 71, 165-173 (1981) $^{2}$H.F. King and S. Havriliak, private communication $^{3}$J.P. Champion and G. Pierre, J. Mol. Spectrosc. 79, 255-280 (1980)