Lifetimes of pre-reactive complexes of peroxy radicals revisited: thermostat effects, temperature dependence and highly oxygenated molecules†

Abstract

In recent work [Daub et al., ACS Earth Space Chem., 2022, 6, 2446] we have developed a simple model for describing the lifetime of pre-reactive complexes, and demonstrated its use for predicting the reactivity of barrierless reactions between peroxy radicals. Here, we modify and extend the method in three important ways. First, we compare the use of a Langevin thermostat for initial equilibration of the system with the Nosé–Hoover thermostat. Then, we show some new results for the lifetimes of complexes of secondary and tertiary ozonolysis and hydroxyl radical products from α-pinene. Finally, we use the method to measure the temperature dependence of complex lifetimes and compare them with available experimental results for reaction rates as a function of temperature.