Electron-impact excitation of the normal vibrational modes of NH sub 3 in the intermediate region (12--50 eV)

Journal Article · Mon Jan 01 04:00:00 EST 1990 · Journal of Chemical Physics; (USA)

DOI:https://doi.org/10.1063/1.458465· OSTI ID:7243794

Furlan, M; Hubin-Franskin, M; Delwiche, J; Collin, J E ^[1]

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1. Laboratoire de Spectroscopie d'Electrons Diffuses, Institut de Chimie, Bat. B6, Universite de Liege, Sart Tilman par 4000 Liege 1, Belgium (BE)

Electron-impact excitation of the normal vibrational modes of NH{sub 3} 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 {ital v}=0{r arrow}1 transitions have been measured at various scattering angles ranging from 8{degree} to 60{degree}. 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 {nu}{sub 2} differential cross section is forward peaked, whereas that of {nu}{sub 4} is isotropic. The differential cross section of {nu}{sub 1,3} composite has a minimum at 30{degree}. At 25 eV the angular behavior of the differential cross sections is roughly similar for all the normal modes with a minimum at 30{degree}, but the values (in arbitrary units) below and above 30{degree} are quite different for each normal mode.

• OSTI ID: 7243794
• Journal Information: Journal of Chemical Physics; (USA), Journal Name: Journal of Chemical Physics; (USA) Vol. 92:1; ISSN JCPSA; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
AMMONIA
COLLISIONS
CROSS SECTIONS
DIFFERENTIAL CROSS SECTIONS
ELECTRON COLLISIONS
ELECTRON SPECTROSCOPY
ELECTRON-MOLECULE COLLISIONS
ENERGY LEVELS
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EV RANGE
EV RANGE 10-100
EXCITATION
EXCITED STATES
HYDRIDES
HYDROGEN COMPOUNDS
MOLECULE COLLISIONS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
SPECTROSCOPY
VIBRATIONAL STATES