Development and characterization of a laser-induced acoustic desorption source

TL;DR

This paper introduces a laser-induced acoustic desorption source with a novel aerosol spraying method for uniform sample coverage, enabling stable measurements and detailed characterization of molecular plumes for use at large facilities.

Contribution

It presents a new laser-induced acoustic desorption source with a unique aerosol deposition technique and comprehensive plume analysis, advancing sample delivery methods for molecular spectroscopy.

Findings

Translational velocity remains constant across laser intensities.

Translational temperature increases with laser fluence.

Higher laser fluence leads to more molecular fragmentation.

Abstract

A laser-induced acoustic desorption source, developed for use at central facilities, such as free-electron lasers, is presented. It features prolonged measurement times and a fixed interaction point. A novel sample deposition method using aerosol spraying provides a uniform sample coverage and hence stable signal intensity. Utilizing strong-field ionization as a universal detection scheme, the produced molecular plume is characterized in terms of number density, spatial extend, fragmentation, temporal distribution, translational velocity, and translational temperature. The effect of desorption laser intensity on these plume properties is evaluated. While translational velocity is invariant for different desorption laser intensities, pointing to a non-thermal desorption mechanism, the translational temperature increases significantly and higher fragmentation is observed with increased desorption laser fluence.