The MD simulation of thermal properties of plutonium dioxide

摘要

The thermodynamic properties of PuO_2 have been investigated between 300 and 3000 K by molecular dynamics (MD) simulation with empirical interaction potential. The properties include melting point, lattice parameter variation, enthalpy and heat capacity. The melting point of two-phase simulation (TPS) is in agreement with the experimental value, and it gives a much lower value than one-phase simulation (OPS). The lattice parameter and heat capacity at high temperatures are expressed as a(T)=5.381784.38×10~(-5)T6.5525×10~(-9)T20.9362×10~(-12)T3 and CP(KJ·mol-~1· K-~1)=18648.8e474.5 /T/(T2(e474.5/T-1)2)9.337×10~(-6)T, respectively. True linear thermal expansion coefficient (TLTEC) α is about 8.89×10~(-6) K~(-1) at 300 K. Our simulation results are in good agreement with experimental and other theoretical data.