Investigation of new nuclei formation during heteromolecular nucleation using an adiabatic pulsed condensation nuclei counter

The hypothesis that stable angstrom-sized embryos are coalesced by water condensation into larger embryos was investigated. A modified Pollak condensation nucleus counter, using controlled condensation-evaporation cycle, demonstrated incremental steps of heteromolecular nucleation from allegedly particle free air. Analysis of 58 air samples demonstrated discrete periodic production of nuclei beyond normal nucleation levels. Oscillations in the condensation nuclei count and the number of nucleation-condensation cycles required to create the first burst in nuclei count are identified as characteristics of new nuclei formation. Different pore sizes of the mixed cellulose ester filters used to clean the initial "particle free" air correlated with the initial size distribution of the embryos present in the Pollak counter. The findings are in agreement with classical nucleation theory, previous studies of reactive species nucleation, and modeling of nanoparticle production via vapor condensation. From this work stable angstrom-sized embryos of different sizes were concluded to exist, and their presence would tend to corrupt experiments on homogeneous nucleation of water. Moreover, this research presents a new adiabatic expansion methodology to investigate the activity of the underlying embryo population during nucleation experiments and to measure air quality as a function of subcritical-sized contaminants.