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O: Fachverband Oberflächenphysik
O 58: Mini-Symposium: Molecular scale investigations of liquid-vapor interfaces II
O 58.2: Talk
Wednesday, March 3, 2021, 11:00–11:20, R1
Modelling solvation at dielectric interfaces — •Jakob Filser1, Markus Sinstein1, Konstantin Jakob1, Karsten Reuter2, and Harald Oberhofer1 — 1Technische Universität München — 2Fritz-Haber-Institut der Max-Planck-Gesellschaft
Modelling solvation effects is a complex challenge in molecular simulations. The difficulty lies in unravelling classical electrostatic, quantum mechanical, nuclear, entropic and other free energy contributions in liquid systems. In reality these contributions interact with each other and a simplistic separation is not possible. Modelling this full complexity by accounting for all relevant degrees of freedom explicitly is often computationally intractable. Therefore, approximations are necessary. The family of implicit solvation models treats only the solute on an explicit, atomistic level and summarizes the degrees of freedom of all or all but few solvent molecules in a structurless dielectric medium.
The presence of dielectric interfaces in the system further complicates things. Different models which predict similar energies in bulk solvent can predict substantially different behaviour at a dielectric interface. We systematically construct a method which can implicitly model dielectric interfaces. It describes a solvent only by three parameters, the first of which is experimentally known: The relative permittivity, a dimensionless interaction distance and an effective interfacial tension with the explicit system. First predictions are compared to experimental results as well as predictions from explicit solvent models for an octanoic acid surfactant on water droplets.