Divesh Bhatt1, Zhenhua Li2, Donald G. Truhlar2, and J. Ilja Siepmann3. (1) Department of Chemistry, University of Minnesota, P190 Kolthoff Hall, Minneapolis, MN 55455, (2) Chemistry, University of Minnesota, Minneapolis, MN 55455, (3) University of Minnesota, Department of Chemistry, Minneapolis, MN 55455-0431
Nucleation and growth of Al nanoparticles in the vapor phase are studied using analytic potential energy functions that give an accurate representation of the bulk vapor-liquid coexistence curve. At several temperatures above the bulk melting point, standard state Gibbs free energy changes for the reactions relevant to the growth of nanoparticles of size n (i.e., Al(n)+Al = Al(n+1)) and nucleation barriers are calculated via Monte Carlo simulations. An umbrella sampling potential is utilized to sample all relevant cluster sizes efficiently in a single simulation. The standard-state free energy change increases with temperature, and the reactions are exothermic. Additionally, the standard state free energy change approaches a constant value with increase in cluster size.