Dissociative electron attachment and anion-induced dimerization in pyruvic acid

Area of Science:

• Physical Chemistry
• Chemical Physics
• Molecular Dynamics

Background:

• Dissociative electron attachment (DEA) is a fundamental process in chemistry and physics.
• Understanding DEA to organic molecules like pyruvic acid is crucial for fields such as radiation chemistry and astrobiology.
• Pyruvic acid is a key metabolite, and its interaction with electrons is relevant to biological systems.

Purpose of the Study:

• To investigate the partial cross sections and fragmentation dynamics of dissociative electron attachment to pyruvic acid.
• To elucidate the complex rearrangement reactions occurring during the dissociation process.
• To identify the mechanisms responsible for the formation of fragment anions at low electron energies.

Main Methods:

• Experimental measurement of partial cross sections for dissociative electron attachment to pyruvic acid.
• Theoretical electronic structure calculations to model dissociation pathways.
• Analysis of fragment anion yields as a function of electron energy.

Main Results:

• A rich fragmentation dynamics was observed for pyruvic acid upon electron attachment.
• Electronic structure calculations identified complex rearrangement reactions during dissociation.
• Fragment anions were observed at electron energies near 0 eV, suggesting secondary reactions.
• These secondary reactions, involving transient anions and neutral molecules, were found to be unusually efficient.

Conclusions:

• The dissociation of pyruvic acid via electron attachment involves intricate rearrangement mechanisms.
• Secondary reactions, particularly those proceeding through double-hydrogen-bonded complexes and ultrafast proton transfer, are significant pathways for anion formation at low energies.
• These findings provide new insights into the complex electron-molecule interactions of biologically relevant molecules.