Femtosecond photoelectron circular dichroism of chemical reactions

TL;DR

This paper introduces a time-resolved photoelectron circular dichroism technique using ultrashort VUV pulses to monitor chiral changes during chemical reactions, providing new insights into reaction dynamics.

Contribution

It demonstrates the first table-top VUV-TRPECD method capable of resolving chirality changes in real-time during photodissociation of chiral molecules.

Findings

Resolved chirality changes during iodine photodissociation

Identified key features of TRPECD in reaction dynamics

Validated experimental results with high-level ab-initio calculations

Abstract

Understanding the chirality of molecular reaction pathways is essential for a broad range of fundamental and applied sciences. However, the current ability to probe chirality on the time scale of chemical reactions remains very limited. Here, we demonstrate time-resolved photoelectron circular dichroism (TRPECD) with ultrashort circularly polarized vacuum-ultraviolet (VUV) pulses from a table-top source. We demonstrate the capabilities of VUV-TRPECD by resolving the chirality changes in time during the photodissociation of atomic iodine from two chiral molecules. We identify several general key features of TRPECD, which include the ability to probe dynamical chirality along the complete photochemical reaction path, the sensitivity to the local chirality of the evolving scattering potential, and the influence of electron scattering off dissociating photofragments. Our results are interpreted by comparison with novel high-level ab-initio calculations of transient PECDs from molecular photoionization calculations. Our experimental and theoretical techniques define a general approach to femtochirality.