Performance of Kobryn-Gusarov-Kovalenko closure from a thermodynamic viewpoint for one-component Lennard-Jones fluids

Highlights: • A vertical rise is observed in the curve of differentiation of RDF under KGK closure. • KGK closure underestimates internal energy and pressure when the density is low. • KGK closure shows a similar behavior to HNC and KH closures at high density region. • Density dependence of isothermal compressibility shows a turnover under KGK closure. • Energy and virial equations are consistent under KGK and KH closures. The performance of Kobryn-Gusarov-Kovalenko (KGK) closure was examined in terms of the thermodynamics for one-component Lennard-Jones fluids. The result was compared to molecular dynamics simulation as well as to hypernetted chain, Kovalenko-Hirata (KH), Percus-Yevick and Verlet-modified closures. As the density increases, the error of KGK closure shows a turnover, regarding the excess internal energy, pressure and isothermal compressibility. On the other hand, it was numerically confirmed that the energy and the virial equations are consistent under both KH and KGK closures. The accuracies of density-derivative and temperature-derivative of the radial distribution function are also discussed.