Homogeneous nucleation of water vapor in inert gas atmospheres
"The homogeneous nucleation of water vapor in atmospheres of helium, neon, argon, krypton, and xenon was studied using an expansion type cloud chamber. A strong dependence of the nucleation rate on the particular inert carrier gas was observed. At present the only dependence upon the nature of the carrier gas included in classical nucleation theories is a small factor arising from kinetic considerations which is in the wrong direction to explain the observations. To explain the dependence of the rate on the nature of the carrier gas, a molecular cluster model is assumed allowing inert gas atoms to occupy the cavities in a clathrate-like structure. The envelopment of the carrier gas atoms in these cavities results in a substantial interaction energy. The law of mass action is applied to this hydration reaction to achieve the dependence of the nucleation rate on the nature for the carrier gas. Since detailed computations were undertaken for only one cluster size, namely a 57 molecule four celled cluster, the results apply to only one supersaturation. The results are in reasonable agreement with experiment considering the degree of approximation made in the computations. This work indicates further the power of molecular treatments to treat subtleties in the nucleation process which cannot be effectively handled by the classical theory"--Abstract, pages iii-iv.
Missouri University of Science and Technology
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