Liquid-vapour phase diagram and surface tension of the Lennard-Jones core-softened fluid

In the present work, we consider different fluids described by the same functional form of the Lennard-Jones core-softened (LJCS) truncated and shifted interaction potential, which covers fluids from double well to single well and repulsive shoulder. The liquid-vapour phase diagram and surface tension is studied by means of Molecular Dynamics simulation in the canonical ensemble. Density profiles, orthobaric densities, vapour pressure, surface tension and critical points are investigated. The systematic determination of interface properties allows us to elucidate the influence of a second characteristic length in the interaction potential. Simulation results are analysed in the framework of the principle of corresponding states, and it is shown that the liquid-vapour coexistence satisfies the principle at a certain degree. Finally, we demonstrate that fluids with lambda < 0 follow the Ising universality class. (C) 2020 Elsevier B.V. All rights reserved.