Low-energy electron collisions with proline and pyrrolidine: A comparative study

Area of Science:

• Atomic and Molecular Physics
• Quantum Chemistry
• Biophysics

Background:

• Understanding electron interactions with biomolecules is crucial for radiobiology and astrobiology.
• Amino acids like proline play vital roles in biological systems.
• Pyrrolidine is a fundamental structural component of proline.

Purpose of the Study:

• To compute and compare elastic electron scattering cross sections for proline and pyrrolidine.
• To identify and characterize shape resonances in these molecules.
• To elucidate the contributions of the carboxylic group and pyrrolidine ring to proline's electronic structure.

Main Methods:

• Employed the Schwinger multichannel method with pseudopotentials.
• Calculated integral, differential, and momentum transfer cross sections up to 15 eV.
• Utilized the static-exchange plus polarization approximation.

Main Results:

• Identified three shape resonances for proline (1.7 eV, 6.8 eV, 10 eV) and two for pyrrolidine (7 eV, 10.2 eV).
• Found good agreement between calculated resonance energies and experimental data.
• Attributed proline's 1.7 eV resonance to the carboxylic group and higher resonances to the pyrrolidine ring.

Conclusions:

• The study provides valuable cross-section data for electron-molecule collisions involving proline and pyrrolidine.
• Resonance structures reveal distinct electronic properties influenced by molecular fragments.
• Findings contribute to a deeper understanding of electron interactions with biologically relevant molecules.