Temperature Dependence of Vibrational Relaxation from the Upper Vibrational Levels of HF and DF.
AEROSPACE CORP EL SEGUNDO CA AEROPHYSICS LAB
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Room temperature quenching rate coefficients for relaxation from the upper vibrational levels of HF and DF have been successfully duplicated with good agreement with available experimental data. This agreement was obtained with the use of a rotational nonequilibrium model and rate coefficients computed by Wilkins. The key processes are V to R and R to V mechanisms, which give the problem a multiple-channel nature. The model provided temperature-dependent quenching rate coefficients for relaxation of HFv and DFv by HFv 0 and DFv 0. The temperature dependence is predicted to be similar to that measured for HFv 1 HF and its isotopic analogs. The results of this study indicate that HFv HFv 0, DFv DFv 0, DFv HFv 0, HFv DFv 0 all scale as v to the nth power with n varying between 2.3 and 1.6 as v increases from 2 to 6. With the appropriate fine structure rate coefficients, this model should be equally applicable to vibrational relaxations from the upper vibrational levels of other hydrogen-halide molecules. This theoretical study is the first in which the temperature dependence of the V to R rate coefficients for HFv sub 1 HFv sub 2 0 and its isotopic analogs have been predicted over the entire temperature range from 300 to 2400 K.
- Inorganic Chemistry
- Atomic and Molecular Physics and Spectroscopy