Nuclear quantum effects on the quasiparticle properties of the chloride anion aqueous solution within the GW approximation

TL;DR

This study uses advanced quantum simulations to show that nuclear quantum effects slightly improve the accuracy of predicted electronic structures of chloride ions in water, aligning better with experimental data.

Contribution

It introduces a combined approach of path-integral ab initio molecular dynamics and GW approximation to account for nuclear quantum effects in ion-water electronic structure calculations.

Findings

NQEs improve agreement with experimental photoelectron spectra.

NQEs weaken hybridization between chloride ions and water molecules.

NQEs have a small but significant impact on electronic structure predictions.

Abstract

Photoelectron spectroscopy experiments in ionic solutions reveal important electronic structure information, in which the interaction between hydrated ions and water solvent can be inferred. Based on many-body perturbation theory with GW approximation, we theoretically compute the quasiparticle electronic structure of chloride anion solution, which is modeled by path-integral $ab$ $initio$ molecular dynamics simulation by taking account the nuclear quantum effects (NQEs). The electronic levels of hydrated anion as well as water are determined and compared to the recent experimental photoelectron spectra. It is found that NQEs improve the agreement between theoretical prediction and experiment because NQEs effectively weaken the hybridization of the between the $\rm Cl^-$ anion and water. Our study indicates that NQEs plays a small but non-negligible role in predicting the electronic structure of the aqueous solvation of ions of the Hofmeister series.