Abstract
An expression is derived for the pressure dependence of a chemical activation unimolecular rate constant at a fixed total energy and angular momentum in terms of the distribution of unimolecular lifetimes. This rate constant is shown to have a certain insensitivity at low pressures to the form of the lifetime distribution. A kinetic model is then introduced based on a finite rate of intramolecular vibrational energy redistribution. The model provides an analytical explanation of a recent finding in a trajectory calculation for a particular chemical activation system, that the chemical activation unimolecular rate constant at low pressures equals the τ = 0 microcanonical value even though the unimolecular lifetime distribution is highly non-RRKM. A similar result is predicted for a class of such systems. Implications are described.
Original language | English |
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Pages (from-to) | 6717-6720 |
Number of pages | 4 |
Journal | Journal of physical chemistry |
Volume | 88 |
Issue number | 26 |
DOIs | |
State | Published - 1984 |