“…[37,40,41] Under nonequilibrium situations such as gases under a heat flux or a shear flow, their pure nonequilibrium contributions to the rate of chemical reaction have also attracted much attention. [39,43,44,45,46,47,48,49] Since nonequilibrium correction terms of the chemical reaction rate are quadratic functions of nonequilibrium fluxes, the explicit nonequilibrium velocity distribution function of the Boltzmann equation for hard-core molecules to second order is needed to derive it based on the line-of-centers model. [39,43,45,46] The pure effect of a heat flux on the chemical reaction rate has been recently calculated using the second-order velocity distribution function of the Boltzmann equation for hard-core molecules.…”