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Halogenation effects on electron collisions with CF3Cl, CF2Cl2, and CFCl3
T C Freitas1, A R Lopes2, A D Azeredo3
1Tecnologia em Luteria, Universidade Federal do Paraná, 81520-260 Curitiba, Paraná, Brazil.
The Journal of Chemical Physics
|May 2, 2016
Summary
This study calculates electron collision cross sections for chlorofluorocarbons (CF3Cl, CF2Cl2, CFCl3) using the Schwinger multichannel method. Results show good agreement with experimental data and highlight a halogenation effect on molecular resonances.
Area of Science:
- Atomic and Molecular Physics
- Quantum Chemistry
- Chemical Physics
Background:
- Low-energy electron collisions with molecules are crucial for understanding chemical processes in various environments.
- Chlorofluorocarbons (CFCs) have environmental significance, and their interaction with electrons is important for atmospheric chemistry.
- Accurate theoretical models are needed to predict electron scattering cross sections for these molecules.
Purpose of the Study:
- To compute differential and integral elastic electron scattering cross sections for CF3Cl, CF2Cl2, and CFCl3.
- To investigate the influence of the permanent electric dipole moment on scattering cross sections.
- To analyze the electronic structure and resonance phenomena in these molecules.
Main Methods:
- Schwinger multichannel method with pseudopotentials.
- Static-exchange and static-exchange plus polarization approximations.
- Born closure scheme for dipole moment influence.
- Electronic structure calculations.
Main Results:
- Calculated cross sections show very good agreement with experimental data from Jones, Mann, Linder, and Hoshino et al.
- Good agreement with R-matrix calculations by Beyer et al. regarding resonance positions.
- Qualitative agreement with independent atom method calculations above 20 eV.
- Identified a linear relationship between resonance stabilization and lowest unoccupied molecular orbital energy, indicating a halogenation effect.
Conclusions:
- The Schwinger multichannel method provides accurate cross sections for low-energy electron scattering with CFCs.
- The study confirms the importance of electron-molecule interactions in understanding CFC behavior.
- The observed halogenation effect offers a signature for understanding molecular property trends in related compounds.
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