Molecular dynamics of nondegenerate hydrogen plasma using improved Kelbg pseudopotential with electron finite-size correction

Abstract: This paper is devoted to semiclassical molecular dynamics simulation of nondegenerate hydrogen plasma using an improved Kelbg pseudopotential. The main novelty of our method is accounting for the finite size of electrons. This modification resolves the nonphysical cluster formation at temperatures below 50 kK, which was first reported by A.V. Filinov [Phys. Rev. E 70, 046411 (2004)]. However, the energy still appears to be underestimated at low temperatures, as indicated by comparisons with the recent path integral Monte Carlo calculations [Phys. Plasmas 31, 110501 (2024)]. Using the presented method, we analyze the dependence of radial distribution functions, composition, ionization degree, energy, and pressure on the plasma coupling parameter, while maintaining a fixed degeneracy parameter. Additionally, we demonstrate the impact of incorporating long-range interactions on the energy $N$-dependence by utilizing the angular-averaged Ewald potential. Finally, we compute the thermodynamic limits for energy and pressure.