An algorithm for calculating the movements of diatomic gases molecules

The problem of modeling the properties of diatomic gases by molecular dynamics methods is considered. Such studies are traditional for the physics of matter. Currently, there is an increased interest in this problem in connection with the development of nanotechnologies and their implementation in various industrial branches. In the proposed work, the question of clarifying the original classical model of Newton's dynamics is considered. In particular, a technique is discussed for taking into account additional degrees of freedom that characterize the rotational motions of diatomic molecules. This is due to the need to correctly calculate the heat capacity. To solve this problem, it was proposed to add equations for the angular momentum and rotational velocities of molecules to the molecular dynamics model. For such an extended formulation, a special numerical algorithm has been developed that generalizes the Verlet scheme. A computational program has been developed on the basis of the proposed algorithm. It was used to calculate the heat capacity curve for nitrogen in the temperature range 100-400 K at a pressure of 1 atm. The calculated data obtained agree with the known data from reference books.