Iterative charge equilibration for fourth-generation high-dimensional neural network potentials

Bibliographic Details
Title: Iterative charge equilibration for fourth-generation high-dimensional neural network potentials
Authors: Kocer, Emir, Singraber, Andreas, Finkler, Jonas A., Misof, Philipp, Ko, Tsz Wai, Dellago, Christoph, Behler, Jörg
Publication Year: 2025
Collection: Condensed Matter
Subject Terms: Condensed Matter - Materials Science
More Details: Machine learning potentials (MLP) allow to perform large-scale molecular dynamics simulations with about the same accuracy as electronic structure calculations provided that the selected model is able to capture the relevant physics of the system. For systems exhibiting long-range charge transfer, fourth-generation MLPs need to be used, which take global information about the system and electrostatic interactions into account. This can be achieved in a charge equilibration (QEq) step, but the direct solution (dQEq) of the set of linear equations results in an unfavorable cubic scaling with system size making this step computationally demanding for large systems. In this work, we propose an alternative approach that is based on the iterative solution of the charge equilibration problem (iQEq) to determine the atomic partial charges. We have implemented the iQEq method, which scales quadratically with system size, in the parallel molecular dynamics software LAMMPS for the example of a fourth-generation high-dimensional neural network potential (4G-HDNNP) intended to be used in combination with the n2p2 library. The method itself is general and applicable to many different types of fourth-generation MLPs. An assessment of the accuracy and the efficiency is presented for a benchmark system of FeCl$_3$ in water.
Document Type: Working Paper
Access URL: http://arxiv.org/abs/2502.07907
Accession Number: edsarx.2502.07907
Database: arXiv
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