The model that describes elastic collisions between atoms/molecules is one of the most important inputs to the simulation of gas flows governed by the Boltzmann equation whether solved deterministically or using methods such as direct simulation Monte Carlo(DSMC).While most of these models assume a purely repulsive interaction between gas atoms/molecules,there are recent publications that considered the implementation of the realistic attractive-repulsive Lennard–Jones(LJ) model in DSMC simulations as well as in solutions of the linearized Boltzmann equation.