Low-energy elastic electron scattering from ethylene: Elastic scattering and vibrational excitation
M. A. Khakoo1,*, S. M. Khakoo2, A. Sakaamini1, B. A. Hlousek1, L. R. Hargreaves1, J. Lee3, R. Murase3
1 Department of Physics, California State University, Fullerton, CA 92831, USA
2 Department of Chemistry & Biochemistry, California State University, Fullerton, California 92831, USA
3 Troy High School, 2200 Dorothy Lane, Fullerton, California 92831, USA
Published 20 January 2016
Abstract. Normalized experimental differential and integral cross sections for elastic and vibrationally inelastic scattering of low-energy electrons from ethylene (C2H4) have been measured over a large number of incident electron energies and angles. The differential cross sections are measured at incident energies from 0.5 to 100 eV and scattering angles from 5∘ to 130∘. These measurements are made to monitor the role of the 2B2g (≈1.8eV) and the higher 2B2u+2B1u+2Ag (≈7.5eV) resonances in the scattering dynamics. Our differential cross section measurements are in very good to excellent agreement with past measurements, and in reasonable agreement with theory as regards forward scattering. A feature in the elastic cross section at 90∘ scattering angle at ≈3.5eV is tentatively associated with the onset of excitation of the ∼a 3B1u triplet electronic state. Differential cross sections for vibrational excitation of four composite energy features in ethylene are also presented from incident energies of 1.25–15 eV. These results are compared to previous measurements with satisfactory results regarding resonant behavior of these features also concerning the role of the 2B2g (≈1.8eV) and the higher 2B2u+2B1u+2Ag (≈7.5eV) resonances in the scattering dynamics.