Spatial Decay and Limits of Quantum Solute-Solvent Interactions

TL;DR

This study investigates how solvent molecules influence the ionization energy of phenol using the GW approximation, revealing a decay pattern of solvation effects and proposing a model for predicting ionization energies in various solvents.

Contribution

It introduces a fragment-based analysis of solvation effects and establishes a 9 angstrom cutoff for effective solvent interactions, along with a predictive model for ionization energies.

Findings

Electronic effects vary by up to 0.4 eV among solvents.

Correlation energy decay is independent of solvent type.

A 9 angstrom cutoff defines the effective solvation volume.

Abstract

Molecular excitations in the liquid-phase environment are renormalized by the surrounding solvent molecules. Herein, we employ the GW approximation to investigate the solvation effects on the ionization energy of phenol in various solvent environments. The electronic effects differ by up to 0.4 eV among the five investigated solvents. This difference depends on both the macroscopic solvent polarizability and the spatial decay of the solvation effects. The latter is probed by separating the electronic subspace and the GW correlation self-energy into fragments. The fragment correlation energy decays with increasing intermolecular distance and vanishes at ~9 angstroms, and this pattern is independent of the type of solvent environment. The 9 angstrom cutoff defines an effective interacting volume within which the ionization energy shift per solvent molecule is proportional to the macroscopic solvent polarizability. Finally, we propose a simple model for computing the ionization energies of molecules in an arbitrary solvent environment.