8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

Fri 911:10-14:00P6.39Aerosol growth analysis based on various seed types bymolecular dynamicsDonguk Suh 1 and Kenji Yasuoka 11 Keio University, 3-14-1 Hiyoshi, Kohokuku, 223-0061, Yokohama, JapanCondensation on a spherical, cubic, rod-shaped seed particle was simulated by classical moleculardynamics. Seed size, shape, and supersaturation ratio of the system were the factors that wereexamined in order to observe the effects of the dimension of seeds and thermodynamic conditions.Two stages of nucleation were found to exist within the system regardless of the seed type,where the first stage is from the seed growth and the second from homogeneous nucleation. TheYasuoka-Matsumoto method was used to calculate the nucleation and growth rate. The homogeneousnucleation characteristics coincided with the classical nucleation theory. However, thegrowth characteristics showed a discrepancy with the classical nucleation theory, because no supersaturationratio influence could be observed. Cluster formation free energy and kinetic analysiswere also performed to calculate the critical nucleus size and better understand the seed growthcharacteristics. The seed size was found to have a reciprocal effect on the growth rate, but showedto be insignificant on the homogeneous nucleation characteristics for this system. The criticalnucleus size from kinetic analysis showed a greater difference compared to the first nucleationtheorem, classical nucleation theory, or free energy analysis. The growth rate of the cubic seedwas five to ten times faster compared to the spherical seed, when the seed consisted of the samenumber of molecules. All in all, the classical nucleation theory showed relatively good agreementcompared to previous nucleation studies by molecular dynamics.39