Abstract
The nonequilibrium velocity distribution and reaction rate in fast ion–molecule reactions with non-Langevin reaction cross sections are studied using the Monte Carlo simulation in steady-state systems where ions are diluted in heat-bath reactant molecules and ion sources compensate the loss of ions due to the reaction. The non-Langevin reaction cross sections are taken as the power and exponential dependences on the collision energy and the elastic cross section is taken as the hard-sphere model. The ion velocity distribution and temperature and the reaction rate constant indicate significant deviations from equilibrium.