Influence of Curvature on the Transfer Coefficients for Evaporation and Condensation of Lennard-Jones Fluid from Square-Gradient Theory and Nonequilibrium Molecular Dynamics

The influence of curvature on heat and mass transfer across interfaces is often significant in nanoscopic systems. An important example is the initial growth phase of bubbles and droplets in nucleation processes, where they have radii of only a few nanometers. Curvature can be consistently handled within the framework of nonequilibrium thermodynamics by expanding the interface transfer coefficients in the total and Gaussian curvatures. We formulate the coefficients in this expansion analytically and calculate them to second order along the vapor-liquid coexistence line of the Lennard-Jones fluid, which models argon to a good accuracy. To achieve this, square-gradient theory is combined with nonequilibrium molecular dynamics. We discuss how the coefficients depend on the temperature and the truncation value of the interaction potential. The presented coefficients can be used directly to describe heat and mass transfer across interfaces of bubbles/droplets in the Lennard-Jones fluid with cylindrical, spherical, or complex geometries.