Predictive possibilities of unimolecular rate theory

Abstract

This paper describes the calculation of rate constants for thermal unimolecular reactions and recombinations at the low pressure limit, at the high pressure limit, and in the intermediate falloff range, as well as the calculation of specific rate constants for unimolecular rearrangements. The most uncertain factors of the theory are identified by comparison with the NO/sub 2/, ClNO, H/sub 2/O, and O/sub 3/ systems. Weak collision and centrifugal barrier effects are discussed for low pressure rate constants. Simplified adiabatic channel calculations are proposed for specific rate constants and high pressure rate constants. Reduced falloff curves are presented in factorized form with weak collision and strong collision broadening factors. Simple falloff expressions are derived. 5 figures, 44 references, 3 tables.