Fluctuation statistical theory of nucleation in water vapors at near-critical temperatures

The Monte Carlo method has been used to study the evolution of the statistical behavior of density fluctuations in water vapors when approaching the critical isotherm from low temperatures. The free energy, work, and entropy of the formation of the nanosize density fluctuations have been calculated numerically. The spontaneous formation of the critical nucleus of the condensed phase is possible only against the back-ground of the density fluctuations with dimensions exceeding a certain threshold value $n^*$, which increases rapidly when the critical temperature is approached. One should expect a qualitative change in the mechanism of the growth of nuclei of the condensed phase in the region of near critical temperatures from the statistically independent acts of the absorption of monomers by the surface of a microdroplet to the strongly correlated density fluctuations of expanding spatial dimensions.