Observation of photoelectron circular dichroism using a nanosecond laser

TL;DR

This paper demonstrates that photoelectron circular dichroism (PECD) can be observed using a nanosecond laser, showing similar magnitude to femtosecond methods but with added spectral information, simplifying its application in analytical chemistry.

Contribution

It shows that multiphoton PECD can be measured with nanosecond lasers, expanding the technique's accessibility and providing insights into intermediate molecular states.

Findings

PECD observed with nanosecond UV pulses

PECD magnitude comparable to femtosecond ionization

Intermediate states influence photoelectron spectra

Abstract

Photoelectron circular dichroism (PECD) is a fascinating phenomenon both from a fundamental science aspect but also due to its emerging role as a highly sensitive analytic tool for chiral recognition in the gas phase. PECD has been studied with single-photon as well as multi-photon ionization. The latter has been investigated in the short pulse limit with femtosecond laser pulses, where ionization can be thought of as an instantaneous process. In this contribution, we demonstrate that multiphoton PECD still can be observed when using an ultra-violet nanosecond pulse to ionize chiral showcase fenchone molecules. Compared to femtosecond ionization, the magnitude of PECD is similar, but the lifetime of intermediate molecular states imprints itself in the photoelectron spectra. Being able to use an industrial nanosecond laser to investigate PECD furthermore reduces the technical requirements to apply PECD in analytical chemistry.