Glycine in aerosol water droplets: A critical assessment of Köhler theory by predicting surface tension from molecular dynamics simulations
- ISSN: 16807316
- DOI: 10.5194/acp-11-519-2011
Aerosol particles in the atmosphere are important participants in the formation of cloud droplets and have sig- nificant impact on cloud albedo and global climate. Accord- ing to the K¨ ohler theory which describes the nucleation and the equilibrium growth of cloud droplets, the surface tension of an aerosol droplet is one of the most important factors that determine the critical supersaturation of droplet activation. In this paper, with specific interest to remote marine aerosol, we predict the surface tension of aerosol droplets by perform- ing molecular dynamics simulations on two model systems, the pure water droplets and glycine in water droplets. The curvature dependence of the surface tension is interpolated by a quadratic polynomial over the nano-sized droplets and the limiting case of a planar interface, so that the so-called Aitken mode particles which are critical for droplet forma- tion could be covered and the K¨ ohler equation could be im- proved by incorporating surface tension corrections.