Low-energy electron scattering from halomethanes. II. Direct and resonant vibrational excitation in e-CF4scattering
- 1 January 1992
- journal article
- Published by IOP Publishing in Journal of Physics B: Atomic, Molecular and Optical Physics
- Vol. 25 (2) , 545-556
- https://doi.org/10.1088/0953-4075/25/2/021
Abstract
For pt.I see ibid., vol.25, no.2, p.533-43 (1992). Vibrational excitation of CF4 by electron impact has been studied in a crossed-beam experiment for collision energies from approximately 0.5-12 eV. Two regions of strong inelastic scattering are observed, a resonance region between 6 and 11 eV and a region of direct excitation below 2 eV. Excitation of the nu 3 asymmetric stretch mode is the dominant energy loss process over the entire range of collision energies. At low energies, it is excited by direct scattering via the dipole moment, whereas in the resonance region the mode selectivity is caused by the dominant influence of the T2 (C-F sigma *) resonance. The excitation behaviour of other modes (including overtones and combination modes) is discussed in the paper. The assignment of the T2 (C-F sigma *) and A1 (C-F sigma *) resonances as well as their role in vibrational excitation and dissociative attachment are discussed. For energies below 5 eV, the results are roughly described by the Born dipole approximation and confirm the expected large inelastic cross sections below E=2 eV.Keywords
This publication has 24 references indexed in Scilit:
- Low energy electron impact excitation of dipole allowed vibrations in CO and CO2Journal of Physics B: Atomic, Molecular and Optical Physics, 1990
- A theory of low-energy electron impact excitation of dipole-allowed molecular vibrations. An application to acetylene, C2H2Journal of Physics B: Atomic, Molecular and Optical Physics, 1990
- Electron-elastic scattering in the static-exchange approximationPhysical Review A, 1988
- Electron swarm characteristic energies (Dr/μ) in tetrafluoromethane (CF4) at low E/NJournal of Physics D: Applied Physics, 1988
- Selectivity in resonant vibrational excitation by e− impact (0.3–4.5 eV) on formaldehyde, acetaldehyde and acetoneChemical Physics, 1987
- Selection rules for vibrational energy loss by resonant electron impact in polyatomic moleculesPhysical Review A, 1986
- Vibrational Contributions to Molecular Dipole PolarizabilitiesJournal of Physical and Chemical Reference Data, 1982
- Negative ion formation in CF2Cl2, CF3Cl and CFCl3 following low energy (0—10 eV) impact with near monoenergetic electronsChemical Physics, 1979
- Partitioning of excess energy in dissociative resonance capture processesThe Journal of Chemical Physics, 1974
- Angular distributions for the excitation of vibronic states by resonant electron molecule reactionsJournal of Physics B: Atomic and Molecular Physics, 1971