Theory of nucleation of water. I. Properties of some clathrate-like cluster structures

• Published in: Journal of colloid and interface science 1972, Vol.39 (1), p.65-78
• Main Authors: Daee, M, Lund, L.H, Plummer, P.L.M, Kassner, J.L, Hale, B.N
• Format: Article
• Language: English
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/0021-9797(72)90143-9

The tranquility of classical homogeneous nucleation theory has been disturbed by the introduction of statistical mechanical correction factors to a basically thermodynamic theory. These factors, which appear to be essential, destroy much of the agreement with experiment in the case of water vapor. A molecular model for the prenucleation water clusters is proposed with a view toward resolving some of these difficulties. As a first step, the properties of a few specific cluster configurations have, been examined. Clathrate-like structures containing 16 to 57 water molecules are discussed. The hydrogen bonds were treated as simple harmonic oscillators for the purpose of calculating normal mode frequencies. The Helmholtz free energy of formation of the cluster is calculated from the appropriate partition functions. For these clathrate-like structures the free energy of formation was not found to be a smoothly increasing function of the number of molecules but showed minima corresponding to closed cages.