PREDISSOCIATION AND ROTATIONAL ENERGY TRANSFER IN CH $B^{2}\Sigma^{+} (\nu^{\prime}=0, N^{\prime}>14; \nu^{\prime}=1, N^{\prime}>6)$
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Date
1995
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Ohio State University
Abstract
Fluorescence lifetimes have been determined for individual rotational levels near the predissociation limit in the $B^{2}\Sigma^{+}$ state of CH. The method is a measurement of relative quantum yields from laser-induced fluorescence intensities in a low pressure methane/oxygen flame. Levels studied are $N^{\prime} = 15$ to 17 in $\nu^{\prime} = 0, and N^{\prime} = 7$ and 8 in \nu^{\prime} = 1$. The collision free lifetimes decrease very quickly with increasing $N^{\prime}$: for example, in $\nu^{\prime} = 0, \tau(N^{\prime} = 15) = 150$ ns and $\tau (N^{\prime} = 17) \sim 1$ ns. Theoretical $calculations^{1}$ agree well with these results. The competition between collisional, predissociative, and radiative processes has been studied for these peculiar rotational levels, and a model for state-specific rotational energy transfer has been tested in this electronic state.
Description
1. N. Elander, M. Hehenberger, and P. R. Bunker, Phys. Scripta 20, 631 (1979). Supported by the Physical Sciences Department of the Gas Research Institute.
Author Institution: SRI International, Menlo Park, CA 94025.
Author Institution: SRI International, Menlo Park, CA 94025.