Force fields, free energy and fog: modelling the nucleation of atmospheric aerosol

CCMMP Seminars
Prof Ian Ford
Prof Martin Dove & Dr A. J. Misquitta
November 25th, 2014 at 14:00
GO Jones Room 610

The air we breathe carries a sprinkling of micro- and nanoparticles, also known as aerosol. These particles play a role in climate change, since fog and clouds are essentially atmospheric aerosol particles made visible by water condensation. About half of all atmospheric aerosol is formed in situ, but from what gas phase precursors? The usual suspects are sulphuric acid and water, though there are others. In this talk I shall discuss some of the challenges of modelling aerosol nucleation and describe a new phenomenological force field for clusters of sulphuric acid and water molecules. I shall go on to describe how we calculate cluster free energies by guided disassembly, and how this leads to predictions of the nucleation rate, but I shall present results only for pure water clusters at present, alas!