Molecular Description of the Surface Tension of Curved Interfaces

A comparison is made between the traditional stress-tensor based approach to the local pressure in a curved liquid-vapor interface and a novel purely thermodynamic approach. While both approaches are equivalent for planar interfaces, the stress-tensor based approach becomes ambiguous on a molecular scale for curved interfaces. We illustrate how the value of the surface tension and the location of the surface of tension can be obtained from the thermodynamic approach when the pressure profile of a spherical interface is computed within a molecular dynamics simulation.