Development and Characterization of a Laser-Induced Acoustic Desorption Source

Area of Science:

• Physical Chemistry
• Materials Science
• Analytical Chemistry

Background:

• Laser-induced acoustic desorption (LIAD) is a crucial technique for generating molecular plumes.
• Characterizing these plumes is essential for optimizing LIAD performance in various applications.
• Existing LIAD sources often face limitations in measurement duration and sample uniformity.

Purpose of the Study:

• To present a novel laser-induced acoustic desorption source designed for central facilities like free-electron lasers.
• To introduce and validate an aerosol-based sample deposition method for uniform coverage.
• To comprehensively characterize the molecular plume generated by the LIAD source and investigate the influence of laser intensity.

Main Methods:

• Development of a laser-induced acoustic desorption source with a fixed interaction point for prolonged measurements.
• Implementation of a novel aerosol spraying technique for uniform sample deposition.
• Utilization of strong-field ionization for universal detection and characterization of the molecular plume (density, spatial extent, fragmentation, temporal distribution, velocity, temperature).

Main Results:

• The aerosol spraying method resulted in uniform sample coverage and stable signal intensity.
• Molecular plume properties, including density, spatial extent, fragmentation, temporal distribution, translational velocity, and temperature, were successfully characterized.
• Translational velocity remained invariant with varying desorption laser intensity, suggesting a nonthermal mechanism.
• Translational temperature and fragmentation increased significantly with higher desorption laser fluence.

Conclusions:

• The developed LIAD source and aerosol deposition method provide a robust platform for molecular plume studies.
• The findings offer insights into the fundamental mechanisms of laser-induced acoustic desorption.
• The characterized plume properties are critical for optimizing LIAD applications in areas such as mass spectrometry and materials analysis.