An alternative view of unimolecular reaction theory

Abstract

A primitive form of unimolecular reaction theory is constructed, based on the master equation. Application of the theory depends upon the way in which eigenvalues of large stochastic matrices behave as certain of the matrix elements are varied. Some of the required eigenvalue properties have been deduced by numerical experiment, and others are available from earlier work on diatomic dissociation reactions. Comparison of the results from this primitive approach with those of existing theories of unimolecular reactions suggests some reinterpretation of parameters used in those theories: most interestingly, the number of effective oscillators occurring in Kassel theory (or its Slater-theory equivalent) appears to be the ratio, at infinite pressure, of the total rate to the rate of the only reaction channel which survives at the low-pressure limit.