Stability of pyruvic acid clusters upon slow electron attachment

Area of Science:

• Astrochemistry
• Chemical Physics
• Astrobiology

Background:

• Pyruvic acid is vital for prebiotic chemistry and may form on interstellar ices.
• Understanding pyruvic acid's stability in space is key to astrobiology.
• Electron-induced decomposition is a potential degradation pathway in the interstellar medium.

Purpose of the Study:

• To investigate the stability of pyruvic acid clusters under electron impact.
• To determine how clustering affects pyruvic acid's fragmentation pathways.
• To explore the role of water in stabilizing pyruvic acid.

Main Methods:

• Electron attachment experiments on pyruvic acid clusters (homomolecular and heteromolecular).
• Mass spectrometry to analyze fragmentation patterns and electron energy dependence.
• Ab initio calculations to support fragmentation pathway assignments.
• Electron energy loss spectroscopy and photochemical calculations to study excited states.

Main Results:

• Clustering dramatically reduces pyruvic acid fragmentation by electrons.
• Heteromolecular clusters of pyruvic acid with water show the strongest stabilization, favoring non-dissociative attachment.
• In homomolecular clusters, dehydrogenation remains active over a wider electron energy range compared to isolated molecules.
• Excited state data explains clustering-induced stabilization effects.

Conclusions:

• Clustering, especially with water, significantly enhances pyruvic acid stability in interstellar conditions.
• This enhanced stability supports the presence and role of pyruvic acid in prebiotic interstellar chemistry.
• The findings provide insights into molecular survival and evolution on interstellar ices.