A large nonequilibrium effect of decrease of the bimolecular chemical reaction rate in a dilute gas

The perturbation solution of the Boltzmann equation is used to analyze the relative decrease η(T) of the rate constant k(T) of a chemical reaction in a dilute gas in the temperature T. The Prigogine–Xhrouet model of the reactive cross-section is introduced for the reaction A+A⇄B+B. A large effect for η(T) equal even nearly 75% ( for a small reduced threshold energy ε0 and a large molar fraction xB) follows from the analytical solution for k(T). A replacement of T by the Shizgal–Karplus nonequilibrium temperatures TA and TB in the equilibrium rate constants (for the forward and reverse reactions) gives η(TA,TB) confirming this effect.