Molecular structure retrieval directly from laboratory-frame photoelectron spectra in laser-induced electron diffraction

TL;DR

This paper presents a novel, straightforward method for retrieving molecular structures directly from laboratory-frame photoelectron spectra using laser-induced electron diffraction, improving accuracy for complex molecules.

Contribution

The authors introduce a simple, critical-point-based retrieval technique for molecular structures from LIED spectra, outperforming traditional Fourier methods in accuracy and simplicity.

Findings

Successfully retrieved the structure of OCS molecule.

Method accurately captures asymmetric bond stretching and bending.

Confirmed results with quantum-classical calculations.

Abstract

Ubiquitous to most molecular scattering methods is the challenge to retrieve bond distance and angle from the scattering signals since this requires convergence of pattern matching algorithms or fitting methods. This problem is typically exacerbated when imaging larger molecules or for dynamic systems with little a priori knowledge. Here, we employ laser-induced electron diffraction (LIED) which is a powerful means to determine the precise atomic configuration of an isolated gas-phase molecule with picometre spatial and attosecond temporal precision. We introduce a simple molecular retrieval method, which is based only on the identification of critical points in the oscillating molecular interference scattering signal that is extracted directly from the laboratory-frame photoelectron spectrum. The method is compared with a Fourier-based retrieval method, and we show that both methods correctly retrieve the asymmetrically stretched and bent field-dressed configuration of the asymmetric top molecule carbonyl sulfide (OCS), which is confirmed by our quantum-classical calculations.