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O: Fachverband Oberflächenphysik

O 85: New Methods: Theory

O 85.5: Vortrag

Donnerstag, 20. März 2025, 11:30–11:45, H25

Efficient treatment of long-range electrostatics in charge equilibration approaches — •Kamila Savvidi, Ludwig Ahrens-Iwers, and Robert Meißner — Hamburg University of Technology, Hamburg, Germany

We present a charge equilibration (QEq) method in the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) based on real-space Gaussians of width η_i as charge densities. This implementation builds on the ELECTRODE package, which already supports Gaussian charge densities [1]. In addition, an efficient particle-particle particle-mesh k-space solver [2] is used, which significantly improves the computational performance compared to existing QEq implementations in LAMMPS. We validate our approach with the test cases of Ti/TiOx and SiO2 polymorphs. In the limit of very narrow Gaussians, we were able to show that our algorithm converges to EEM results for the case of Ti/TiOx. By fitting the Coulomb energy of two isolated Gaussian charge distributions to the repulsion between two Slater-type orbitals, optimized widths for Si and O were obtained that led to results in good agreement to previous studies using STOs instead of Gaussians.

[1] Ludwig J. V. Ahrens-Iwers, Mathijs Janssen, Shern R. Tee, Robert H. Meißner; ELECTRODE: An electrochemistry package for atomistic simulations. J. Chem. Phys. 28 August 2022; 157 (8) [2] Ahrens-Iwers LJV, Meißner RH. Constant potential simulations on a mesh. J Chem Phys. 2021 Sep 14;155(10)