A molecular dynamics study on plutonium mononitride

Abstract

The physico-chemical properties of plutonium mononitride (PuN) were estimated by molecular dynamics (MD) calculation. The parameters of the interatomic potential were determined by fitting the changes in the lattice parameters with temperature and pressure to the literature data. The thermal expansion coefficient ( α) and the compressibility ( β) were calculated. The heat capacity at constant volume ( C V) was evaluated from the variation of the internal energy of the system by the fixed volume MD calculation. The lattice dilational contribution to the heat capacity ( C d) was calculated from α and β. The MD calculation results ( C V+ C d) agree with the reported values. The thermal conductivity ( λ) was calculated using the Green–Kubo relation in the temperature range of 300 to 2000 K. The temperature dependence of the calculated thermal conductivity followed a 1/ T law, which indicates that the lattice contribution to the thermal conductivity ( λ lat) could be evaluated by the molecular dynamics calculation. In the present study it was found that the MD simulation technique is useful and applicable to estimate the physico-chemical properties of PuN.