  Molecular dynamics (MD) simulation is applied to the condensation process of
supersaturated vapors of methane, ethane, and carbon dioxide. Simulations of
systems with up to a million particles were conducted with a massively parallel
MD program. This leads to reliable statistics and makes nucleation rates down
to the order of 10^30/(m^3 s) accessible to the direct simulation approach.
Simulation results are compared to the classical nucleation theory (CNT) as
well as the theory of Laaksonen, Ford, and Kulmala (LFK) which introduces a
size dependence of the specific surface energy. CNT describes the nucleation of
ethane and carbon dioxide excellently over the entire studied temperature
range, whereas LFK provides a better approach to methane at low temperatures.
