AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Determination of the Binding Rate for Nanoclusters in the Gas Phase via Molecular Dynamics
EIRINI GOUDELI, Huan Yang, Christopher Hogan Jr., University of Minnesota
Abstract Number: 29 Working Group: Aerosol Physics
Abstract The earliest stages of nanoparticle formation and growth in the gas phase involve collisions and subsequent binding/reaction between molecular (or atomic) monomers and a growing nanocluster. In modelling nanocluster collisional growth rates, simplified approaches are often adopted, in which the binding rate (collision + sticking rate) is calculated assuming hard-sphere potential interactions between colliding entities and assuming a sticking efficiency of 100%. This approach neglects potential interactions between monomers and nanoclusters and does not accurately consider kinetic energy to internal energy exchange during collision (i.e. the assumption of perfect sticking is akin to assuming all monomer kinetic energy is lost during collision).
In this presentation, we show that it is possible to utilize Molecular Dynamics (MD) simulations to examine nanocluster-monomer collisions and sticking with accurate description of potential interactions (which increases the binding rate as compared to the hard-sphere approach) and kinetic-internal energy exchange during collision (which decreases the binding in comparison to conventional approaches). A framework is presented in which the binding probability is systematically determined as a function of monomer relative velocity, impact parameter, and nanocluster temperature. The binding rate can be determined directly once the binding probability function is obtained. Specific examples for Au nanoclusters and polyaromatic hydrocarbon clusters with short chain alkenes (precursors to soot) are provided.