Multiple-well master equation study on the propargyl plus indenyl recombination and subsequent reactions

The reaction between propargyl and indenyl radicals is investigated focusing primarily on the reaction pathways leading to the formation of acenaphthylene. The potential energy surfaces for recombination of the two radicals, isomerization and dissociation of the adducts, and some subsequent reactions are explored using the CBS-QB3// omega B97X-D and CASPT2 quantum chemical methods. Several reaction pathways for the formation of tricyclic species, which eventually produce acenaphthylene, are identified. The rate constants for reactions involved in these and some other competing pathways are obtained from solutions to the master equations, which provide the steady-state and phenomenological descriptions on the kinetics of the multiple-well systems. The results indicate that acenaphthylene can be formed via roughly three different routes, depending mainly on tempera-ture. A simplified reaction mechanism describing the kinetics of the major reaction pathways is proposed for use in kinetic modeling.