Homogeneous nucleation of a homologous series of n-alkanes (CiH2i+2, i=7–10) in a supersonic nozzle

Homogeneous nucleation rates of the n-alkanes (CiH2i+2; i=7–10) were determined by combining information from pressure trace measurements and small angle x-ray scattering (SAXS) experiments in a supersonic Laval nozzle. The condensible vapor pressure pJ max, the temperature TJ max, the characteristic time ΔtJ max, and supersaturation SJ max corresponding to the peak nucleation rate Jmax were determined during the pressure trace measurements. These measurements also served as the basis for the subsequent SAXS experiments. Fitting the radially averaged SAXS spectrum yielded the mean droplet radius ⟨r⟩, 5<⟨r⟩/nm<31, the width of the aerosol size distribution σ, 2<σ/nm<6, and the particle number density N, 7×1010supersaturations SJmax are on the order of 105. In spite of these extr...