Size-Resolved Photoelectron Anisotropy of Gas Phase Water Clusters and Predictions for Liquid Water

TL;DR

This study measures size-resolved photoelectron angular distributions of water clusters up to 20 molecules, revealing a decrease and eventual convergence in anisotropy, and uses this data to predict liquid water anisotropies with good agreement.

Contribution

First measurement of size-resolved photoelectron anisotropy in water clusters and development of a scattering model to predict liquid water anisotropies.

Findings

Anisotropy decreases with cluster size up to 5-6 molecules

Anisotropy converges for larger clusters

Predicted liquid water anisotropies agree with experimental data

Abstract

We report the first measurement of size-resolved photoelectron angular distributions for the valence orbitals of water clusters with up to 20 molecules. A systematic decrease of the photoelectron anisotropy is found for clusters with up to 5-6 molecules, and most remarkably, convergence of the anisotropy for larger clusters. We suggest the latter to be the result of a local short-range scattering potential that is fully described by a unit of 5-6 molecules. The cluster data and a detailed electron scattering model are used to predict liquid water anisotropies. Reasonable agreement with experimental liquid jet data is found.