Role of range of interaction potential on structure and dynamics of a one-component system of particles interacting via Mie potential

Abstract

The thermodynamic and transport properties of a fluid depend significantly on the particle interactions at the molecular level. The range of these interparticle interactions thus plays a crucial role in determining its phase behavior. In the present work, we study the role of the range of particle–particle interaction potential on the structure and dynamics of a two-dimensional fluid in the proximity of the liquid–solid phase transition using molecular dynamics simulations. The particles are considered to interact via a Mie (2n, n) potential, and the range of this potential is varied by changing the attractive exponent n from 4 to 20. As the range of interaction potential is increased, a decrease in the local structural order is observed, while the sixfold orientational order remains almost invariant. Some exceptions are observed for the longest range of interaction potential at the liquid–solid phase transition temperature. Furthermore, we observe a temperature-dependent crossover in the relaxation of the nearest-neighbor correlations and the self-diffusion coefficient with a change in the interaction range. This results in a similar crossover in the Stokes–Einstein relation of the two-dimensional system of particles. In addition, we observe a deviation from the conventional Stokes–Einstein relation in systems interacting via these Mie potentials.