Electron scattering from gas-phase glycine molecules

Area of Science:

• Theoretical Chemistry
• Atomic and Molecular Physics
• Quantum Chemistry

Background:

• Understanding electron-molecule interactions is crucial for various chemical and biological processes.
• Glycine, the simplest amino acid, plays a fundamental role in biological systems, making its electron collision dynamics of significant interest.

Purpose of the Study:

• To investigate low-energy electron collisions with gas-phase glycine molecules.
• To identify and characterize resonant states in glycine using advanced computational methods.
• To compare theoretical predictions with experimental data for electron-glycine interactions.

Main Methods:

• Utilized the fixed-nuclei R-matrix method for electron collision calculations.
• Employed state-averaged complete-active-space self-consistent-field (CASSCF) orbitals.
• Included 40 electronic states of neutral glycine, encompassing Rydberg states, in the R-matrix model.

Main Results:

• Identified a significant peak in the elastic cross section around 3.4 eV due to a pi(*) shape resonance.
• Observed numerous sharp peaks in elastic and inelastic cross sections above 5 eV, attributed to core-excited resonances.
• Rydberg orbitals were found to be essential for describing core-excited resonances in inelastic cross sections, though their impact on elastic scattering was minor.

Conclusions:

• The theoretical resonance positions generally agree well with experimental findings for dissociative electron attachment to glycine.
• The study provides valuable insights into the complex electron-glycine collision dynamics.
• This work contributes to a deeper understanding of electron interactions with biologically relevant molecules.