 
Summary: A random walk through the dynamics of homogeneous vaporliquid
nucleation
David M. Huang and Phil Attarda
School of Chemistry, University of Sydney, New South Wales 2006, Australia
Received 11 January 2005; accepted 8 February 2005; published online 29 April 2005
A method of calculating rates of homogeneous vaporliquid nucleation based on Langevin dynamics
of a few relevant degrees of freedom on a freeenergy surface is proposed. The surface is obtained
here from simulation and from a semi empirical expression. The mass and friction coefficients are
derived from atomistic umbrellasampling moleculardynamics simulations. The calculated
nucleation rate agrees with atomistic simulations for one particular state point of the LennardJones
fluid. The present method is about four orders of magnitude more computationally efficient than the
direct atomistic simulation of the transmission coefficient. © 2005 American Institute of Physics.
DOI: 10.1063/1.1884086
I. INTRODUCTION
Classical nucleation theory CNT provides a simple
analytic expression for the rate of homogeneous vaporliquid
nucleation by relying on several assumptions. One such as
sumption is that the growing liquid droplet is spherical in
shape and of uniform liquid density. The free energy of
nucleation at a given temperature and supersaturation is a
