Homogeneous nucleation rate measurements in 1-pentanol vapor with helium as a buffer gas

Abstract

The rate of homogeneous nucleation in supersaturated vapors of n-pentanol was studied experimentally using an upward static diffusion chamber. Helium was used as a buffer gas, holding the total pressure in the chamber at P t=25 kPa. A recently improved photographic technique was used to determine the nucleation rate as a function of supersaturation at temperature T=260 K. This dependence was compared with predictions made by the classical theory of homogeneous nucleation. Furthermore, the influence of gaseous ions on nucleation rate was studied, and a minimum voltage across the chamber, necessary to avoid nucleation on ions, was determined. The effect of the wall heating power on nucleation was found to be negligible in the range studied.