LASER-INDUCED FLUORESCENCE FROM THE $A^{2}\Delta, B^{2}\Pi, C^{2}\Sigma^{+}$ AND $G^{2}\Sigma^{-}$ STATES OF THE NS $RADICAL^{\ast}$
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Date
1984
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Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
Laser-induced fluorescence has been observed from transitions between $A^{2}\Delta, B^{2}\Pi, C^{2}\Sigma^{+}$, and $G^{2}\Sigma^{-}$ and the $X^{2}\Pi$ ground state of the NS molecule. NS was monitored in a flow reactor downstream from a low pressure microwave discharge in $SF_{6}$ and $N_{2}$. Laser radiation tunable from 2.8.8-336.0 nm with bandwidth $0.3 cm^{-1}$ was produced by Raman shifting a frequency doubled dye Laser. Rotationally resolved fluorescence excitation spectra of $A^{2}\Delta. v'=0-1; B^{2}\Pi, v'=0-12$; and $C^{2}\Sigma^{+}, v^{\prime}=0$ been observed. Relative band emission strengths for 12 bands of $A^{2}\Delta, 232$ bands of $B^{2}\Pi$ and 6 bands of $C^{2}\Sigma^{+}$ have been measured and Franck-Condon overlap factors determined. Preliminary observations indicate collision-induced transitions occur between fine structure levels of $B^{2}\Pi$. Rapid collisional quenching of $B^{2}\Pi, v^{\prime}=12$ and $A^{2}\Delta v^{\prime}=0$ (but not $A^{2}\Delta v^{\prime}=1$ or $B^{2}\Pi v^{\prime}=1-11$) suggests collisional mixing with predissociative levels. Lifetime measurements for $B^{2}\Pi$ and the observed collisional quenching of $B^{2}\Pi, v^{\prime}=12$ are in agreement with the recent results of Matsumi $et at.^{1}$
Description
$^{\ast}$ Supported by the National Science Foundation, Grant No. CPE-80-17521. $^{1}$ Y. Matsumi, T. Munakata, and T. Kasuya, J. Phys. Chem. 88, 264 (1984).
Author Institution: Chemical Physics Laboratory, SRI International
Author Institution: Chemical Physics Laboratory, SRI International