# Unravelling the influence of quantum proton delocalization on electronic charge transfer through the hydrogen bond

## TL;DR

This paper investigates how nuclear quantum effects influence electronic charge transfer in hydrogen bonds, revealing that quantum nuclear motion significantly alters charge transfer magnitude and temperature dependence, crucial for accurate modeling.

## Contribution

It demonstrates that nuclear quantum effects are essential for understanding charge transfer in hydrogen bonds and identifies a geometric parameter that governs this transfer.

## Key findings

- Quantum nuclear effects cause large changes in charge transfer magnitude.
- Charge transfer exhibits significant temperature dependence due to quantum effects.
- A single geometric parameter determines charge transfer in hydrogen bonds.

## Abstract

Upon hydrogen bond formation, electronic charge density is transferred between the donor and acceptor, impacting processes ranging from hydration to spectroscopy. Here we use ab initio path integral simulations to elucidate the role of nuclear quantum effects in determining the charge transfer in a range of hydrogen bonded species in the gas and liquid phase. We show that the quantization of the nuclei gives rise to large changes in the magnitude of the charge transfer as well as its temperature dependence. We then explain how a single geometric parameter determines the charge transfer through the hydrogen bond. These results thus demonstrate that nuclear quantum effects are vital for the accurate description of charge transfer and offer a physically transparent way to understand how hydrogen bonding gives rise to it.