An x-ray probe of laser-aligned molecules

TL;DR

This paper demonstrates a method using hard x-ray pulses to probe laser-aligned small molecules, enabling potential ultrafast imaging of molecular motions with high spatial resolution.

Contribution

It introduces a novel technique combining laser alignment with x-ray probing to study small molecules at high temporal and spatial resolution.

Findings

Successful alignment of bromotrifluoromethane molecules using optical lasers.

Effective probing of aligned molecules with x-ray pulses tuned to a specific resonance.

Potential for ultrafast imaging of molecular motions at Angstrom resolution.

Abstract

We demonstrate a hard x-ray probe of laser-aligned small molecules. To align small molecules with optical lasers, high intensities at nonresonant wavelengths are necessary. We use 95 ps pulses focused to 40 mum from an 800 nm Ti:sapphire laser at a peak intensity of 10^12 W/cm^2 to create an ensemble of aligned bromotrifluoromethane (CF3Br) molecules. Linearly polarized, 120 ps x-ray pulses, focused to 10 mum, tuned to the Br 1s --> sigma* pre-edge resonance at 13.476 keV, probe the ensemble of laser-aligned molecules. The demonstrated methodology has a variety of applications and can enable ultrafast imaging of laser-controlled molecular motions with Angstrom-level resolution.