Symmetries and selection rules in photoelectron chiral dichroism from tailored light

Fuente: arXiv
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Main Author: Neufeld, Ofer
Format: Preprint
Published: 2025
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author Neufeld, Ofer
author_facet Neufeld, Ofer
contents Photoelectron circular dichroism (PECD) is a method whereby randomly oriented chiral molecules are irradiated by circularly-polarized light, photoionizing electrons, which are measured in a momentum-resolved manner. This scheme permits chiral light-matter interactions within the electric-dipole approximation (avoiding weak magnetic-dipole interactions), yielding huge chiral signals in the form of a forwards-backwards asymmetry in photoemission. Recently, more intricate realizations of PECD have been explored where the circularly-polarized light is replaced with elaborate polarization-tailored light (e.g. bi-chromatic, non-collinear, etc.), some of which do not even require circularly-polarized components, but still lead to massive chiral signals. However, the connection between generalized symmetries and asymmetries of the laser drive and selection rules in PECD have not yet been derived. Here we formulate this connection analytically from group theory, also predicting two previously unknown selection rules for PECD from fields with dynamical inversion and improper-rotational symmetries. We further propose bi-chromatic bi-elliptical fields for breaking symmetries in typical spectra, yielding potentially more information for ultrafast-resolved measurements. We numerically demonstrate all of our results with state-of-the-art ab-initio simulations in the archetypal chiral molecule, Bromochlorofluoromethane, providing predictions for experiments. Our work presents a roadmap for analyzing PECD from tailored light and resolved a long-standing issue in the field. It should motivate theoretical and experimental investigations in novel PECD set-ups.
format Preprint
id arxiv_https___arxiv_org_abs_2505_16273
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Symmetries and selection rules in photoelectron chiral dichroism from tailored light
Neufeld, Ofer
Chemical Physics
Optics
Photoelectron circular dichroism (PECD) is a method whereby randomly oriented chiral molecules are irradiated by circularly-polarized light, photoionizing electrons, which are measured in a momentum-resolved manner. This scheme permits chiral light-matter interactions within the electric-dipole approximation (avoiding weak magnetic-dipole interactions), yielding huge chiral signals in the form of a forwards-backwards asymmetry in photoemission. Recently, more intricate realizations of PECD have been explored where the circularly-polarized light is replaced with elaborate polarization-tailored light (e.g. bi-chromatic, non-collinear, etc.), some of which do not even require circularly-polarized components, but still lead to massive chiral signals. However, the connection between generalized symmetries and asymmetries of the laser drive and selection rules in PECD have not yet been derived. Here we formulate this connection analytically from group theory, also predicting two previously unknown selection rules for PECD from fields with dynamical inversion and improper-rotational symmetries. We further propose bi-chromatic bi-elliptical fields for breaking symmetries in typical spectra, yielding potentially more information for ultrafast-resolved measurements. We numerically demonstrate all of our results with state-of-the-art ab-initio simulations in the archetypal chiral molecule, Bromochlorofluoromethane, providing predictions for experiments. Our work presents a roadmap for analyzing PECD from tailored light and resolved a long-standing issue in the field. It should motivate theoretical and experimental investigations in novel PECD set-ups.
title Symmetries and selection rules in photoelectron chiral dichroism from tailored light
topic Chemical Physics
Optics
url https://arxiv.org/abs/2505.16273