Detecting handedness of spatially oriented molecules by Coulomb explosion imaging

TL;DR

This paper introduces a novel laser-based technique to determine molecular handedness by analyzing Coulomb explosion fragment distributions, offering a new approach to chiral molecule detection with sensitivity comparable to existing methods.

Contribution

The authors develop a computational method for detecting molecular chirality using Coulomb explosion imaging with elliptically polarized lasers, applicable to various chiral molecules.

Findings

Demonstrated computationally for camphor molecules.

Sensitivity to enantiomeric excess comparable to modern methods.

Method can be optimized for different chiral molecules.

Abstract

We present a new technique for detecting chirality in the gas phase: Chiral molecules are spatially aligned in three-dimensions by a moderately strong elliptically-polarized laser field. The momentum distributions of the charged fragments, produced by laser-induced Coulomb explosion, show distinct three-dimensional orientation of the enantiomers, when the laser polarization ellipse is rotated by a non-right angle with respect to the norm vector of the detector plane. The resulting velocity-map-image asymmetry is directly connected to the enantiomeric excess and to the absolute handedness of molecules. We demonstrated our scheme computationally for camphor (C10H16O), with its methyl-groups as marker fragments, using quantum-mechanical simulations geared toward experimentally feasible conditions. Computed sensitivity to enantiomeric excess is comparable to other modern chiroptical approaches. The present method can be readily optimized for any chiral molecule with an anisotropic polarizability tensor by adjusting the polarization state and intensity profile of the laser field.