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Doppler widths in electron quasielastic scattering from molecular gases
1Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel. moreh@bgumail.bgu.ac.il
The Journal of Chemical Physics
|May 12, 2009
Summary
Quasielastic electron scattering reveals molecular gases scatter from single isotopes. Calculations of atomic kinetic energy, including translation, rotation, and vibration, show significant differences from prior estimates.
Area of Science:
- Atomic and Molecular Physics
- Chemical Physics
- Quantum Mechanics
Background:
- Quasielastic electron scattering experiments probe molecular dynamics.
- Previous studies estimated atomic kinetic energy (KE) in molecular gases.
- Understanding atomic KE is crucial for interpreting scattering data.
Purpose of the Study:
- To investigate the nature of scattering in molecular gases at high electron energies.
- To accurately calculate the kinetic energy of scattering atoms within molecules.
- To compare new calculations with existing literature values.
Main Methods:
- Performed quasielastic electron scattering experiments at electron energies (E(e)) >= 1.8 keV.
- Calculated atomic kinetic energy by considering molecular translation, rotation, and vibrational modes.
- Analyzed Doppler broadening of scattered electron lines to infer atomic KE.
Main Results:
- Electron scattering primarily occurs from single isotopes of atomic components in molecular gases.
- Calculated atomic KE values demonstrate significant deviations from literature estimates.
- Doppler broadening directly correlates with the calculated instantaneous KE of scattering atoms.
Conclusions:
- The study provides a more accurate method for determining atomic kinetic energy in molecular gases.
- Experimental results challenge established literature values for atomic KE.
- Findings necessitate a re-evaluation of previous interpretations of quasielastic electron scattering data.
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