Molecular dynamic calculation of diffusion coefficient of gases by the example of argon, nitrogen, hydrogen, oxygen, methane and carbon dioxide

This work is devoted to molecular dynamics calculations of the properties of gaseous media, the study of which is a traditional problem in the physics of matter. The main attention is paid to calculation methods and directly to the calculation of gas self-diffusion coefficients. To simulate the dynamics of gas systems, the equations of Newtonian mechanics are used, the integration of which is carried out using the Velocity Verlet difference scheme. To calculate the diffusion coefficients, Green–Kubo formulas are used. The study was carried out for such gases as argon, nitrogen, hydrogen, oxygen, methane and carbon dioxide at a pressure of 1 atm, in the temperature range of 100–900 K. The obtained calculated gas data are in good agreement with the known theoretical estimates and experimental data.