VIBRATIONAL LEVEL DENSITY AND CORIOLIS COUPLING OF $S_{6} H_{2}CO$ AT 28,000-1
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Date
1989
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Publisher
Ohio State University
Abstract
Stark Level-crossing Spectroscopy was used to study $S_{0} H_{2}CO$ vibrational levels at energies near the dissociation threshold to $H_{2} + CO$. Laser induced fluorescence was detected from $3 S_{1}. 4^{1}, J=1 (1_{01},l_{10}l_{11})$ levels via the $A \leftarrow x$ excitation. A Stark field was applied to induce a resonant interaction between the $S_{1} J=1$ and a $S_0$ single vibration-rotation level. The resonance was identified as a loss in intensity and a shortening of the lifetime in the fluorescence from the $S_{1}$ level. From the different numbers of $S_{1}-S_{0}$ resonances encountered by the $k_{a} = 1$ and $K_{a} = 0 s_1$ levels. It was deduced that the K quantum numbers are mixed by Corlolis coupling. However, the mixing is weak enough to allow the $S_{0}$ levels to retain their individual tuning characteristics. Counting the number of resonances over the Stark tuning range of the $S_{1}$ level and after corrections due to electric field and the Coriolis effects, an $s_{0}$ vibrational level density of $75 \pm 25 per cm^{-1}$ was obtained at $28.300 cm^{-2}$ This number exceeds the best calculated value of $20 per cm^{-1}$ from an anharmonic direct count.
Description
Author Institution: Chemistry Department, University of Pennsylvania