Asymmetry in photoelectron emission from chiral molecules induced by circularly polarized light

Photoelectron angular distributions

Angle-resolved photoelectron spectroscopy has been performed for more than 70 years in various guises, but recently its potential to help solve in detail problems in the photoionization dynamics and intramolecular dynamics of gas-phase molecules has been recognized. One key development has been the design of experiments in appropriate geometries to extract information that pertains to the molecular frame, another has been the development of imaging spectrometers, and a third is the use of ultrafast lasers to cause photoionization. In this review, which is aimed at experimentalists, simple expressions for photoelectron angular distributions (PADs) in various experimental geometries are given and their applications explained.

Observation of a chiral state in a microwave cavity

A microwave experiment has been realized to measure the phase difference of the oscillating electric field at two points inside the cavity. The technique has been applied to a dissipative resonator which exhibits a singularity-called exceptional point-in its eigenvalue and eigenvector spectrum. At the singularity, two modes coalesce with a phase difference of pi/2. We conclude that the state excited at the singularity has a definitive chirality.

A search for circular dichroism in the VUV photofragmentation mass spectra of 2-amino-1-butanol

The dissociative photoionization of a single-enantiomer chiral molecule by circularly polarized synchrotron radiation was investigated, for the first time, in the gas phase. Photoion mass spectra were produced by the interaction of (+)-(S)-, (-)-(R)- and rac-2-amino-l-butanol with circularly polarized light. Comparison of these spectra places an upper bound of approximately 2% on circular dichroism in the dissociative photoionization of 2-amino-l-butanol at 21 eV, which may have consequences for the theory that the origin of biological homochirality was predominantly enantioselective photofragmentation by circularly polarized light. We have also identified and elucidated many of the difficulties of performing gas phase CD measurements in crossed beam experiments.

Circular dichroism in photo-single-ionization of unoriented atoms

We predict circular dichroism in photo-single-ionization angular distributions from spherically symmetric atomic states if the ionized electron is detected using two-slit interferometry. We demonstrate that the resulting electron interference pattern captures phase information on quadrupole corrections to the photoionization amplitude lost in conventional angular distributions.