Electron scattering from gas-phase glycine molecules.

Low-energy electron collisions with gas-phase glycine molecules have been studied using the fixed-nuclei R-matrix method based on state-averaged complete-active-space self-consistent-field orbitals. A total of 40 electronic states of neutral glycine, including 3s and 3p Rydberg excited states, are included in the R-matrix model. A large peak is observed in the A″ partial elastic cross section around 3.4 eV, which originates from the π* shape resonance. In addition, many sharp narrow peaks coming from core excited resonances are seen in the elastic and inelastic cross sections at energies above 5 eV. Although the effect of the Rydberg orbitals on the elastic cross section is insignificant, these orbitals are crucial to represent core excited resonances in the inelastic cross sections. In previous experiments on dissociative electron attachment to gas-phase glycine, noticeable product ion peaks have been observed at electron collision energies around 1–2 and 5–10 eV. The resonance positions obtained in our calculations are generally close to these experimental results. [ABSTRACT FROM AUTHOR]