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Vibrational nonequilibrium effects on diatomic dissociation ratesThe collision-induced dissociation rate of diatomic molecules from a ladder of rotational and anharmonic vibrational states is developed, and the correction for vibrational nonequilibrium is considered. The result is similar to an analytic correction derived by Hammerling et al. (1959) for harmonic oscillators. An empirical correction algorithm suggested by Park (1987, 1990) gives similar results when vibrational temperature is comparable to kinetic temperature but underestimates the dissociation rate when vibrational temperature is small compared with the kinetic temperature. This algorithm uses an effective temperature in the experimentally determined Arrhenius expression for the rate coefficient, which is a weighted average of the vibrational and kinetic temperature, whereas theory indicates that kinetic temperature should appear only in the exponential term of the Arrhenius expression. Nevertheless, an effective temperature can always be found that will numerically duplicate the proper rate coefficient at any given condition, but a constant weighting factor cannot be expected to provide this. However, the algorithm can he adjusted to give reasonable results over a range of conditions if the geometric weighting factor is taken to be a simple linear function of the ratio of vibrational to kinetic temperature in the gas.
Document ID
19930071364
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Hansen, C. F.
(Oregon Univ. Eugene, United States)
Date Acquired
August 16, 2013
Publication Date
November 1, 1993
Publication Information
Publication: AIAA Journal
Volume: 31
Issue: 11
ISSN: 0001-1452
Subject Category
Thermodynamics And Statistical Physics
Accession Number
93A55361
Funding Number(s)
CONTRACT_GRANT: NAG1-1046
Distribution Limits
Public
Copyright
Other

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