American Association for Aerosol Research - Abstract Submission

AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA

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MD Simulation of Surface Tension of Organic Droplets Based on Energy Different Method and Evaporation Correction

XIAOXIANG WANG, Hang Su, Ulrich Poeschl, Yafang Cheng, Max Planck Institute for Chemistry

     Abstract Number: 120
     Working Group: Aerosol Physics

Abstract
Organic aerosols are ubiquitous in the atmosphere and exert a highly effect on health and climate. The properties and behaviours of organic aerosol particles are still poorly understood. Surface tension is one of the important properties for a compound that markedly influences the organic aerosol. In this study, we performed molecular dynamics simulation to determine the surface tension of six n-butanol particles with different radius based on the energy different method. surface tension=(H^combine-(H^droplet+H^gas))/A, where, H represents the enthalpy of different systems in simulation, i.e., n-butanol droplet, nitrogen gas and the combined whole system, and A is the contact surface area between particles and air. This method has been used in some previous studies involved water solution. However, the evaporation process may result in the irregular fluctuations of the enthalpy. To cope with this problem, we introduce an evaporation correction into former equation. surface tension=(H^combine-(H^(droplet-vapor)+H^(gas+vapor)))/A.

Here 'vapor' means the equilibrium number of n-butanol molecules in vapour state. The comparison between values of surface tension with or without evaporation emphasizes the significance of evaporation correction in the calculation.