Molecular modeling of the thermal accommodation of argon atoms in clusters of iron atoms

The interaction of a flow of argon atoms at a temperature of $300$ K with clusters of iron atoms is studied at a cluster temperature of $500$ to $2500$ K. The amount of energy acquired by the argon atom increases, and the thermal-accommodation coefficient decreases according to the Arrhenius law with increasing cluster temperature. The relationship between the coefficient of thermal accommodation and the time of interaction of the incident atom with the cluster is revealed. The heat-transfer coefficient is calculated. The dependences of the thermal-accommodation coefficient and the amount of energy received by an atom on the number of atoms $N$ in the cluster turned out to be linear along $N^{-1/3}$. The method of molecular dynamics is applied. The model consists of a cluster and one incident atom; the trajectories of the incident atom are calculated. The amount of energy produced by an atom and the coefficient of thermal accommodation are found from a comparison of the initial and final velocities of the incident atom. To simulate the flow, $10$ to $300000$ trajectories of the incident atom are averaged with respect to the cluster size.