Electron mean free path from angle-dependent photoelectron spectroscopy of aerosol particles

TL;DR

This paper introduces a novel aerosol-based angle-resolved photoelectron spectroscopy method to measure electron mean free paths in various materials, including liquids, using size-dependent photoemission anisotropy.

Contribution

It demonstrates the feasibility of using aerosol particles and photoemission anisotropy to determine electron mean free paths, expanding applicability to liquids and complex materials.

Findings

Successful simulation fitting to experimental data

Preliminary experimental validation with potassium chloride aerosols

Enhanced information from size-dependent anisotropy

Abstract

We propose angle-resolved photoelectron spectroscopy of aerosol particles as an alternative way to determine the electron mean free path of low energy electrons in solid and liquid materials. The mean free path is obtained from fits of simulated photoemission images to experimental ones over a broad range of different aerosol particle sizes. The principal advantage of the aerosol approach is twofold. Firstly, aerosol photoemission studies can be performed for many different materials, including liquids. Secondly, the size-dependent anisotropy of the photoelectrons can be exploited in addition to size-dependent changes in their kinetic energy. These finite size effects depend in different ways on the mean free path and thus provide more information on the mean free path than corresponding liquid jet, thin film, or bulk data. The present contribution is a proof of principle employing a simple model for the photoemission of electrons and preliminary experimental data for potassium chloride aerosol particles.