Аннотация:Three well-known dissociation models such as Smekhov model, Marrone-Treanor model and Kuznetsov model were compared with quasi-classical calculations for O2 dissociation. New parameters of the models were obtained. The nonequilibrium factors calculated by modified models were in agreement with the results of the quasi-classical calculations and experimental investigations. For checking of new nonequilibrium factor models, the data measured in experiments behind a strong shock wave in O2 were applied. In this case, experimental time profiles of the translational and vibrational temperatures of molecular oxygen were used.