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Low energy electron scattering from selected chlorine-containing hydrocarbons
Abstract
The absolute differential cross sections for elastic scattering and vibrational excitation by electron impact on methyl and ethyl chloride are reported for scattering angles of $30\sp\circ$ and 100$\sp\circ$, at energies below 10 eV. Energy loss measurements are taken at several selected impact energies and the decomposition of the spectra and estimation of the normalized strengths of various vibrational modes are carried out. In addition, angular distributions of the scattered electrons exciting selected vibrational modes at the resonance peaks are reported, and the role of temporary negative states on excitation of the various vibrational modes is explored. Low-lying C-Cl $\sigma\sp*$ resonances for methyl and ethyl chloride are observed at 3.2 and 2.5 eV and have been ascribed to the filling of the 8a$\sb1$ and 14a$\sp\prime$ C-Cl $\sigma\sp*$ orbitals respectively. In addition, two additional resonances for ethyl chloride in the energy range of 4 to 10 eV are detected and have been assigned to the occupation of the 5a$\sp{\prime\prime}$ C-H $\sigma\sp*$ and 15a$\sp\prime$ C-C $\sigma\sp*$ orbitals accordingly. The one associated with the 5a$\sp{\prime\prime}$ C-H $\sigma\sp*$ orbital lies near 4.8 eV and excites mainly the C-H stretching modes. The other lies at a higher energy, near 8 to 9 eV, and excites mainly the bending modes and the C-C stretching mode in ethyl chloride. Exploratory studies are reported on electron scattering from isopropyl chloride and allyl chloride. The relative differential cross sections for elastic scattering and vibrational excitation by electron impact are reported for a scattering angle of 100$\sp\circ$. Energy loss measurements are taken at several selected impact energies, and the decomposition of the energy loss spectra for isopropyl chloride is also presented. The degree of mixing between the nominally $\pi\sp*$ and $\sigma\sp*$ orbitals of allyl chloride appears to be weaker than expected fiom the splitting in energy of the temporary anion states. More detailed measurements will be required to verify this observation.
Subject Area
Atoms & subatomic particles|Molecules
Recommended Citation
Chan, Vincent Keung, "Low energy electron scattering from selected chlorine-containing hydrocarbons" (1995). ETD collection for University of Nebraska-Lincoln. AAI9604404.
https://digitalcommons.unl.edu/dissertations/AAI9604404