 
Summary: CurvatureDependent Surface Tension of a Growing Droplet
Michael P. Moody and Phil Attard
School of Chemistry, University of Sydney, Sydney NSW 2006 Australia
(Received 3 March 2003; published 1 August 2003)
A ghost interface simulation technique is developed and applied to supersaturated LennardJones
liquidvapor interfaces. It is shown that the surface tension decreases approximately linearly with the
supersaturation ratio and that it vanishes at the spinodal. The effect leads to a curvaturedependent
surface tension since, it is argued, the local supersaturation of the vapor above a droplet is greater than
in the bulk due to slow diffusion in the vapor phase. An analytic approximation is given for the local
supersaturation ratio, and an analytic expression for this contribution to Tolman's length is derived. The
theory gives a smaller critical radius and reduces the free energy barrier to nucleation compared to
classical homogeneous nucleation theory, which have important implications for the kinetics of droplet
and bubble formation.
DOI: 10.1103/PhysRevLett.91.056104 PACS numbers: 68.03.Cd, 68.55.Ac, 82.60.Nh
The growth of liquid droplets from a supersaturated
vapor is described by homogeneous nucleation theory,
which expresses the free energy of formation as the sum
of two terms: the surface tension times the interfacial
area, which opposes growth and dominates at small radii,
and a term proportional to the droplet volume that arises
