X-ray diffractive imaging of controlled gas-phase molecules: Toward imaging of dynamics in the molecular frame

TL;DR

This study demonstrates the use of X-ray diffractive imaging combined with laser alignment to determine molecular structures and paves the way for imaging molecular dynamics in the molecular frame.

Contribution

It introduces an experimental approach for imaging aligned gas-phase molecules at high photon energies, enabling future studies of molecular dynamics.

Findings

Achieved 5% agreement between measured and calculated iodine-iodine distances.

Recorded a 2D diffraction pattern of the molecular structure.

Showed potential for imaging molecular dynamics with future high-repetition-rate facilities.

Abstract

We report experimental results on the diffractive imaging of three-dimensionally aligned 2,5-diiodothiophene molecules. The molecules were aligned by chirped near-infrared laser pulses, and their structure was probed at a photon energy of 9.5 keV ($\lambda\approx130 \text{pm}$) provided by the Linac Coherent Light Source. Diffracted photons were recorded on the CSPAD detector and a two-dimensional diffraction pattern of the equilibrium structure of 2,5-diiodothiophene was recorded. The retrieved distance between the two iodine atoms agrees with the quantum-chemically calculated molecular structure to within 5 %. The experimental approach allows for the imaging of intrinsic molecular dynamics in the molecular frame, albeit this requires more experimental data which should be readily available at upcoming high-repetition-rate facilities.