Three-body collision contributions to recombination and collision-induced dissociation. II. Kinetics

Abstract

Detailed rate constants for the reaction Ne+Ne+H⇌Ne2+H are generated, and the master equations governing collision-induced dissociation (CID) and recombination are accurately solved numerically. The temperature and pressure dependence are explored. At all pressures, three-body (3B) collisions dominate. The sequential two-body energy transfer (ET) mechanism gives a rate that is more than a factor of two too small at low pressures and orders of magnitude too small at high pressures. Simpler models are explored; to describe the kinetics they must include direct 3B rates connecting the continuum to the bound states and to the quasibound states. The relevance of the present reaction to more general CID/recombination reactions is discussed. For atomic fragments, the 3B mechanism usually dominates. For diatomic fragments, the 3B and ET mechanism are competitive, and for polyatomic fragments the ET mechanism usually dominates.