Electron-impact excitation of the normal vibrational modes of NH3 in the intermediate region (12–50 eV)
- 1 January 1990
- journal article
- research article
- Published by AIP Publishing in The Journal of Chemical Physics
- Vol. 92 (1) , 213-219
- https://doi.org/10.1063/1.458465
Abstract
Electron‐impact excitation of the normal vibrational modes of NH3 in its ground electronic state has been studied by electron‐energy‐loss spectroscopy in the 12–50 eV impact energy range out of resonances. At 25 and 50 eV the differential cross sections (in arbitrary units) for the elastic scattering process and for the vibrationally inelastic v=0→1 transitions have been measured at various scattering angles ranging from 8° to 60°. The ratio of the vibrational differential cross sections to the elastic one, reported as a function of the impact energy, indicates that for energies above 10 eV, the vibrational excitation occurs mainly through a direct mechanism. At 50 eV the angular shape of the cross sections is strongly dependent on the specific normal mode excited. The ν2 differential cross section is forward peaked, whereas that of ν4 is isotropic. The differential cross section of ν1,3 composite has a minimum at 30°. At 25 eV the angular behavior of the differential cross sections is roughly similar for all the normal modes with a minimum at 30°, but the values (in arbitrary units) below and above 30° are quite different for each normal mode.Keywords
This publication has 32 references indexed in Scilit:
- Rotational branch analysis of the excitation of the fundamental vibrational modes of CO2by slow electron collisionsJournal of Physics B: Atomic and Molecular Physics, 1986
- Electron Energy Loss Spectroscopy in the Study of SurfacesAnnual Review of Physical Chemistry, 1984
- Electron impact cross sections for v=0 to 1 vibrational excitation in CO at electron energies of 3 to 100 eVJournal of Physics B: Atomic and Molecular Physics, 1980
- Elastic scattering and vibrational excitation of CO2by 4, 10, 20 and 50 eV electronsJournal of Physics B: Atomic and Molecular Physics, 1980
- Vibrational Excitation of Polar Molecules by Slow Electrons: HCIPhysical Review Letters, 1977
- Quantum mechanical and crossed beam study of vibrational excitation of N2 by electron impact at 30–75 eVThe Journal of Chemical Physics, 1977
- Vibrational excitation of polar molecules by electron impact. II. Direct and resonant excitation in H2OJournal of Physics B: Atomic and Molecular Physics, 1976
- Vibrational Excitation inby Electron Impact in the 15-35-eV RegionPhysical Review A, 1972
- Gas Phase Raman Intensities: A Review of “Pre-Laser” DataApplied Spectroscopy, 1969
- Forbidden Vibrational Transitions in the Electron-Impact Spectra of Molecular Oxygen and NitrogenThe Journal of Chemical Physics, 1968