Effect of Dipole Asymmetry on Interfacial Ion Distribution in Polar Fluids

Recent studies using first-principles molecular dynamics have shown that water, though electrically neutral, generates strong interfacial electric fields capable of catalyzing atmospheric reactions. We propose that dipole asymmetry, where a molecule's center of geometry is displaced from its center of dipole, may stabilize the reacting charged species at the interface. Using a shifted-dipole Stockmayer fluid model, we previously showed that molecular dipole asymmetry produces preferential molecular orientation at vapor–liquid interfaces, resulting in finite electrostatic potentials and enhanced interfacial organization. In this work, we extend the model by introducing charged species to study how ions interact with varying interfacial polarization. By varying asymmetry in dipole position, dipole strength, and ion concentration, we aim to characterize how electrolyte structure couples with polar fluid organization at both interfaces and in the bulk. This project will provide insights into ion interaction with polar fluids at vapor–liquid interfaces for a fundamental understanding of reactions in atmospheric chemistry and electrochemical systems.