Abstract This computational work was conducted to describe the atomic behavior of Ar atoms in the presence of Cu, Fe, and Cu/Fe nanoparticles via the molecular dynamics (MD) approach. The results of our simulations on the atomic behavior of various structures were reported by calculating physical quantities, such as temperature, total energy, aggregation time, and density/velocity/temperature profile. Computational results revealed that the total energy, the solar energy for instance, converged to a negative value after t = 5 ns. This calculation estimates the atomic stability of nanostructures. Numerically, by adding Cu/Fe nanoparticles to Ar base fluid, the aggregation time in atomic structures increased to 4.59 ns; this atomic improvement could be used for heat/mass transfer aims.