Energetics of Atmospherically Implicated ClustersMade of Sulfuric Acid, Ammonia, and Dimethyl Amine.

The formation ofatmospheric aerosol particles through clusteringof condensable vapors is an important contributor to the overall concentrationof these atmospheric particles. However, the details of the nucleationprocess are not yet well understood and are difficult to probe byexperimental means. Computational chemistry is a powerful tool forgaining insights about the nucleation mechanism. Here, we report accurateelectronic structure calculations of the potential energies of smallclusters made from sulfuric acid, ammonia, and dimethylamine. We alsoassess and validate the accuracy of less expensive methods that mightbe used for the calculation of the binding energies of larger clustersfor atmospheric modeling. The PW6B95-D3 density-functional-plus-molecular-mechanicscalculation with the MG3S basis set stands out as yielding excellentaccuracy while still being affordable for very large clusters. [ABSTRACT FROM AUTHOR]