Project title: Droplets: from molecular nanoclusters to the atmospheric aerosols

Supervisors: George Jackson, Patricia Hunt and Ian Ford

Project description:

Atmospheric aerosols play a key role in affecting climate, pollution and human health by influencing the properties and lifetimes of clouds and precipitation. Despite this, the molecular mechanisms involved in the nucleation of nanoscale liquid droplets are not yet well understood.

Cloud formation is an important climate process, having an effect on the radiative energy balance of the earth. There is a vital link between clouds and non-aqueousaerosols in that they have the ability to act as condensation nuclei on which cloud droplets form. One of the key players in this respect is sulfuric acid, which gets into the atmosphere primarily through fossil fuel burning. Once in the atmosphere, it undergoes ionization in the bulk water, forming a series of ions that themselves act as condensation nuclei.  

The aim of this project as a whole is to understand the underpinning molecular mechanisms involved in nanoscale liquid droplet formation in the atmosphere. The focus will be on sulfuric acid-water droplets and to explore the different scales involved in their formation from small clusters involving just a few acid species and a less than complete water solvation shell all the way up to large nanoscopic atmospheric particulates. Our strategy is to use a combination of quantum mechanical methods, molecular dynamics simulations and coarse-grained theories to obtain accurate information on the mechanical properties and stability of the aggregates involved; and ultimately to understand the nucleation kinetics of these atmospheric systems.