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Low energy (e, 2e) study from the 1t(2) orbital of CH4
1Insititute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China.
The Journal of Chemical Physics
|July 19, 2012
Summary
Electron impact ionization of methane
Area of Science:
- Atomic and Molecular Physics
- Quantum Chemistry
- Electron Scattering
Background:
- Understanding electron-molecule interactions is crucial in various fields.
- Methane (CH4) is a fundamental molecule with significant astrophysical and industrial relevance.
- Previous studies have explored methane ionization, but detailed cross-section analysis remains important.
Purpose of the Study:
- To experimentally and theoretically investigate the single ionization of methane's 1t(2) orbital by 54 eV electron impact.
- To compare measured triple differential cross sections with theoretical models across a wide range of electron emission and scattering angles.
- To identify discrepancies between theory and experiment and explore potential improvements.
Main Methods:
- Experimental measurement of triple differential cross sections (TDCS) for electron impact ionization of methane.
- Theoretical calculations using the distorted wave Born approximation (DWBA) and the molecular three-body distorted wave (M3DW) models.
- Systematic variation of nuclear scattering strength in theoretical models to assess its impact on agreement with experimental data.
Main Results:
- Experimental TDCS were measured over nearly a 4π solid angle for low-energy electron emission.
- Theoretical models (DWBA, M3DW) showed good agreement with experimental data at smaller projectile scattering angles.
- Significant discrepancies between theory and experiment were observed at larger scattering angles.
- Reducing the internuclear distance in theoretical calculations improved agreement with experimental cross sections in both scattering and perpendicular planes.
Conclusions:
- Current theoretical models provide a reasonable description of methane ionization at forward scattering angles.
- Discrepancies at larger angles highlight limitations in existing theoretical frameworks for electron-molecule collisions.
- Adjusting nuclear scattering strength offers a pathway to enhance theoretical accuracy, particularly for understanding electron-hydrogen nucleus interactions.
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