The homogeneous nucleation of cesium vapor

The homogeneous nucleation behavior of supersaturated cesium vapor was investigated in a redesigned upward thermal diffusion cloud chamber in the temperature range between 359 K and 554 K. Critical supersaturations as a function of temperature were measured at temperatures between 359 K and 481 K. The critical cluster sizes (calculated using the Kelvin equation) varied between 12 atoms/cluster at 359 K and 40 atoms/cluster at 554 K. Nucleation rates as a function of supersaturation were measured at temperatures between 508 K and 554 K. The results obtained were compared to the internally consistent version of classical nucleation theory (ICCT). The critical supersaturations measured were about 2-fold larger at 554 K and about 10-fold larger at 359 K than theory predictions. The measured dependence of the nucleation rates on supersaturation was fit accurately by a power law and was weaker than theory prediction. The temperature dependent multiplicative correction to theory necessary for agreement with experiments was large, however, its temperature dependence was similar to that observed in measurements with n-alkanes.