AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Kinetics of Heterogeneous Nucleation in Supersaturated Vapor: Fundamental Limits to Neutral Particle Detection Revisited
ROBERT MCGRAW, Jian Wang, Chongai Kuang, Brookhaven National Laboratory
Abstract Number: 455 Working Group: Aerosol Physics
Abstract We examine the nucleated (with barrier) activation of perfectly wetting (zero contact angle) particles ranging from essentially bulk size down to approximately one nanometer mass diameter. While similar studies trace back to the pioneering work of Fletcher [1958], we present here a novel approach to the analysis based on general area constructions that enable key thermodynamic properties including surface and bulk contributions to nucleation work to be interpreted geometrically with reference to the Kelvin curve. The kinetics of activation is described in more detail in terms of the mean first passage time (MFPT) for barrier crossing. MFPT theory and benchmark calculations are used to develop and test a new approximate but simpler to use analytic expression for barrier crossing rate. The present study is motivated by recent condensation particle counter (CPC) studies that appear to finally establish the long-predicted detection of “sub-Kelvin” particles in the nano-size regime. Corresponding states thermodynamic and kinetic scaling approaches are used to facilitate the correlation and selection of optimal CPC working fluids and operating conditions based on a new metric for heterogeneous nucleation, the signal to noise ratio, and on physical and chemical properties.