Circular dichroism in the photoelectron angular distribution from randomly oriented enantiomers of camphor

Abstract

Circular dichroism in the angular distribution of valence photoelectrons emitted from randomly oriented chiral molecules has been observed in experiments that use circularly polarized VUV synchrotron radiation. Photoionization of the outermost carbonyl oxygen lone pair electrons from pure enantiomers of the prototype chiral molecule camphor is shown to have an asymmetry in the forward–backward scattering of photoelectrons (relative to the propagation direction of the light beam) of magnitude approaching 3% at 9.2 eV photon energy. The asymmetry reverses on exchange of either the helicity of the radiation or of the molecular enantiomer, confirming theoretical predictions of an effect that arises in the pure electric-dipole approximation.