Parkinson, JY;
Lau, GV;
Ford, IJ;
(2016)
Free energy of formation of clusters of sulphuric acid and water molecules determined by guided disassembly.
Molecular Simulation
, 42
(13)
pp. 1125-1134.
10.1080/08927022.2016.1139107.
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Abstract
We evaluate the grand potential of a cluster of two molecular species, equivalent to its free energy of formation from a binary vapour phase, using a non-equilibrium molecular dynamics technique where guide particles, each tethered to a molecule by a harmonic force, move apart to disassemble a cluster into its components. The mechanical work performed in an ensemble of trajectories is analysed using the Jarzynski equality to obtain a free energy of disassembly, a contribution to the cluster grand potential. We study clusters of sulphuric acid and water at 300 K, using a classical interaction scheme, and contrast two modes of guided disassembly. In one, the cluster is broken apart through simple pulling by the guide particles, but we find the trajectories tend to be mechanically irreversible. In the second approach, the guide motion and strength of tethering are modified in a way that prises the cluster apart, a procedure that seems more reversible. We construct a surface representing the cluster grand potential, and identify a critical cluster for droplet nucleation under given vapour conditions. We compare the equilibrium populations of clusters with calculations reported by Henschel et al. [J. Phys. Chem. A 2014;118:2599] based on optimised quantum chemical structures.
| Type: | Article |
|---|---|
| Title: | Free energy of formation of clusters of sulphuric acid and water molecules determined by guided disassembly |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1080/08927022.2016.1139107 |
| Publisher version: | http://dx.doi.org/10.1080/08927022.2016.1139107 |
| Language: | English |
| Additional information: | Copyright © 2016 Informa UK Limited, trading as Taylor & Francis Group. This is an Accepted Manuscript of an article published by Taylor & Francis in Molecular Simulation on 5 July 2016 and available online: http://www.tandfonline.com/doi/full/10.1080/08927022.2016.1139107 |
| Keywords: | Clusters, aerosols, sulphuric acid, nonequilibrium molecular dynamics, nucleation |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/1504853 |
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