Vibrational Nonequilibrium in the Reaction of Hydrogen with Oxygen (Review)

The field of research of vibrational relaxation processes in their interaction with chemical reactions is currently characterized by high activity. This review is based on our work. A vibrational nonequilibrium model of hydrogen oxidation is presented within the framework of a sequential elementary kinetic approach. The central element is to take into account the vibrational nonequilibrium of the HO₂ radical as the most important intermediate in the process of chain branching and in the formation of electronically excited particles. The results of shock wave experiments and corresponding calculations for the H₂ + O₂ + Ar system at temperatures T < 1500 K and pressures p < 4 atm are discussed. It is shown that under these conditions, vibrational nonequilibrium is the most important factor determining the mechanism and rate of the process. The analysis of the thermal effect at various stages of the process, the inhibition of the reaction of hydrogen with oxygen by additives of polyatomic gases and the mechanism of formation of an electronically excited OH(A²Σ⁺) radical is given.