American Association for Aerosol Research - Abstract Submission

AAAR 35th Annual Conference
October 17 - October 21, 2016
Oregon Convention Center
Portland, Oregon, USA

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Properties of Caesium Hydroxide Clusters from Molecular Dynamics Simulations

JULIAN THOMPSON, Conor Galvin, Jonathan Barrett, Michael Rushton, Ian Ford, University College London

     Abstract Number: 333
     Working Group: Aerosol Physics

Abstract
We investigate the nucleation of caesium hydroxide particulates from the vapour by calculating cluster free energies within molecular dynamics. We describe interactions between the caesium and hydroxide ions using screened Coulomb and short-range Buckingham potentials, and consider temperatures where clusters are solid-like and liquid-like. The free energy change associated with the 'mitosis' of a cluster of size N into two clusters of size N/2 is determined from nonequilibrium molecular dynamics simulations using the Jarzynski equality, and a sequence of such operations enables us to compute the free energy of cluster formation from a given vapour phase [1]. The outcome is compared with the predictions of classical nucleation theory, and with an approximation based on the low temperature harmonic dynamics associated with a solid-like cluster.

[1] G.V. Lau, P.A. Hunt, E.A. Mueller, G. Jackson and I.J. Ford, Water droplet excess free energy determined by cluster mitosis using guided molecular dynamics, J. Chem. Phys. 143 (2015) 244709.