A Machine Learning Model for the Chemistry of a Solvated Electron

Fuente: arXiv
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Autores principales: Gao, Ruiqi, Xie, Pinchen, Car, Roberto
Formato: Preprint
Publicado: 2025
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author Gao, Ruiqi
Xie, Pinchen
Car, Roberto
author_facet Gao, Ruiqi
Xie, Pinchen
Car, Roberto
contents In molecular simulations, machine-learning force fields can achieve ab initio accuracy at a lower cost but remain limited in the explicit modeling of electrons. In this work, we develop an electron-aware machine-learning force field, in which an excess electron of interest is modeled quantum mechanically, while the remaining short-range interactions and long-range Coulombic forces are machine-learned to reproduce a density functional theory calculation. We demonstrate the method on the solvated electron in bulk water and its reaction with a hydronium ion. We identify a proton transfer mechanism by which the excess proton recombines with the electron. We determine the forward reaction rates between 350 K and 450 K from first-passage survival functions, which yield an Arrhenius relationship with an activation energy of 3.2 kcal$\cdot$mol$^{-1}$, in good agreement with experiment. From an enhanced sampling simulation, we determine the equilibrium constant, and thus the reaction free energy, which is also consistent with experimental measurements.
format Preprint
id arxiv_https___arxiv_org_abs_2511_22642
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A Machine Learning Model for the Chemistry of a Solvated Electron
Gao, Ruiqi
Xie, Pinchen
Car, Roberto
Chemical Physics
Computational Physics
In molecular simulations, machine-learning force fields can achieve ab initio accuracy at a lower cost but remain limited in the explicit modeling of electrons. In this work, we develop an electron-aware machine-learning force field, in which an excess electron of interest is modeled quantum mechanically, while the remaining short-range interactions and long-range Coulombic forces are machine-learned to reproduce a density functional theory calculation. We demonstrate the method on the solvated electron in bulk water and its reaction with a hydronium ion. We identify a proton transfer mechanism by which the excess proton recombines with the electron. We determine the forward reaction rates between 350 K and 450 K from first-passage survival functions, which yield an Arrhenius relationship with an activation energy of 3.2 kcal$\cdot$mol$^{-1}$, in good agreement with experiment. From an enhanced sampling simulation, we determine the equilibrium constant, and thus the reaction free energy, which is also consistent with experimental measurements.
title A Machine Learning Model for the Chemistry of a Solvated Electron
topic Chemical Physics
Computational Physics
url https://arxiv.org/abs/2511.22642