Gas liquid nucleation, a process by which particles in the atmosphere can form, is a mechanism that is currently not well understood. Often driven by the presence of acidic defects in water clusters, the mechanism is difficult to probe at a molecular level using experimental methods, thereby requiring the use of computational techniques. An additional layer of difficulty in modeling arises from the Grotthus proton shuttling mechanism due to the acidic defects. By this mechanism, an excess proton can traverse multiple water molecules with very little structural rearrangement to the underlying solvation environment. To accurately depict this phenomenon, reactive methodology is imperative. To this end, we are developing a reactive force field based on the empirical valence bond formalism. This force field will be parameterized to ab initio data to accurately model water cluster systems with acid defects such as HCl. Furthermore, the model will be incorporated into efficient enhanced sampling algorithms to extract a molecular level interpretation of the nucleation process and its free energy profile. The development of the force field as well as its ability to model nucleation events accurately will be presented.<br/>

Development of accurate force-fields for water clusters with acidic defects

255th National Meeting (2018)

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