Communications: Evidence for the role of fluctuations in the thermodynamics of nanoscale drops and the implications in computations of the surface tension.

Test-area deformations are used to analyze vapor-liquid interfaces of Lennard-Jones particles by molecular dynamics simulation. For planar vapor-liquid interfaces the change in free energy is captured by the average of the corresponding change in energy, the leading-order contribution. This is consistent with the commonly used mechanical (pressure-tensor) route for the surface tension.