Regensburg 2022 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 46: New Methods and Developments 3: Theory
O 46.1: Vortrag
Mittwoch, 7. September 2022, 15:00–15:15, H6
Atomistic and coarse-grained modelling of liquid-liquid and liquid-gas interfaces — •Jakob Filser1,2, Karsten Reuter1,2, and Harald Oberhofer1,3 — 1Chair of Theoretical Chemistry, TU Munich — 2Theory Department, Fritz Haber Institute Berlin — 3Chair for Theoretical Physics VII, University of Bayreuth
Modelling of dielectric interfaces remains a central challenge in computational chemistry. Liquid-liquid and liquid-gas interfaces have so far received relatively little attention, compared to solid surfaces. We present a new method to incorporate solvation effects into density-functional theory calculations of large organic adsorbates at liquid-liquid and liquid-gas interfaces. Simulating a large number of solvent molecules explicitly at this first-principles level is not computationally tractable. We therefore resort to an implicit solvation approach, treating the solvent as a structureless dielectric medium. Specifically, we advance the multipole-expansion method, in which we model the interface as the boundary of two semi-infinite media with different permittivity. Additionally, we introduce a piecewise expansion of the dielectric response. While the previous version of the MPE method could solve the electrostatic problem only for small solute molecules up to ≈ 10 non-hydrogen atoms, this development now allows us to simulate larger solutes with an overall non-convex hull, with electrostatic interaction energies converged up to few meV. Validating first results of our model for octanoid acid at a water-gas interface by explicit force-field level molecular dynamics simulation provides insight into the role of the atomistic structure of the solvent in the adsorption.