Plume composition and evolution in multicomponent ices using resonant two-step laser ablation and ionization mass...

Area of Science:

• Analytical Chemistry
• Physical Chemistry
• Spectroscopy

Background:

• Laser desorption is crucial for analyzing low-temperature ices.
• Understanding plume dynamics is key to interpreting mass spectrometry data.
• The two-step laser desorption and ionization mass spectrometry (2S-LAIMS) technique offers new analytical capabilities.

Purpose of the Study:

• To investigate the composition and evolution of plumes from resonant infrared laser desorption of ices.
• To characterize the time-resolved behavior of different analytes within the plume.
• To correlate plume distributions with desorption mechanisms and analyte properties.

Main Methods:

• Utilized a two-step laser desorption and ionization mass spectrometry (2S-LAIMS) technique.
• Employed time-of-flight mass spectrometry for plume component analysis.
• Varied the time delay between IR laser desorption and UV laser ionization to build time-resolved plume models.

Main Results:

• Observed complex, time-evolving mass spectral profiles for water ices with mixed analytes.
• Found low-volatility polar analytes and clusters concentrated in the early plume.
• Identified distinct plume components for nonpolar, volatile species, suggesting dual desorption mechanisms (ablation and thermal).

Conclusions:

• Analyte volatility and polarity significantly influence plume composition and distribution.
• Plume velocity distributions provide insights into desorption processes.
• Characterizing plume dynamics aids in identifying unknown compounds and resolving spectral ambiguities in mass spectrometry.