Quantum–Classical Mechanics: Statistical Approach to Molecular Collisions

Abstract

The chaotic dynamics of the transient state in molecular and physicochemical transitions in quantum–classical mechanics is considered in relation to the problem of redistribution of the vibrational–rotational energy of polyatomic molecules M and M1 in their pairwise collisions based on microcanonical distribution. The statistical (canonical) distribution of the probability of energy change due to collisions in the case of a small impurity M in an equilibrium medium of M1 is obtained, as well as all of the moments n of this distribution, which, under the conditions of applicability of the semiclassical approximation for the density of vibrational–rotational states, are some polynomials of the n-th order. The theory is compared with experimental data on monomolecular reactions under low pressures for NO2Cl, C2H5NC, and C5H10 molecules in various gas phase media.

Keywords

• quantum–classical mechanics
• molecular collisions
• polyatomic molecules
• microcanonical distribution for collisions
• canonical distribution for collisions
• moments of canonical distribution for collisions