Near-threshold electronic excitation by electron impact of multilayer physisorbed N/sub 2/ and CO
Electronic excitation of N/sub 2/ and CO condensed (i.e., physisorbed) on a metallic substrate has been investigated by high-resolution electron-energy-loss (HREEL) and low-energy electron-transmission (LEET) spectroscopies in the incident energy range 0--19 eV. The HREEL results yield a more complete picture of the spin-forbidden vibronic bands of the solids than previously available from photon spectroscopies. All levels are found to be shifted down by a few tens of meV and broadened with respect to the gas-phase values. As expected, Rydberg states are absent from such spectra. The LEET experiments provide a measurement of inelastic transitions near the electronic excitation threshold. By recording the second energy derivative of LEET spectra, transitions having a strong cross section near threshold are identified by the sharp structure they produce. These are the a /sup 3/Pi state in CO and, in N/sub 2/, the A /sup 3/..sigma../sub u//sup +/ and B /sup 3/Pi/sub g/ states and a new previously unobserved vibronic band near 12 eV. The magnitudes of thresholds cross sections in the solid phase are discussed in terms of single-electron--molecule scattering mechanisms.
- Research Organization:
- Groupe du Conseil de Recherches Medicales du Canada en Sciences des Radiations, Faculte de Medecine, Universite de Sherbrooke, Sherbrooke, Quebec, Canada J1HX4
- OSTI ID:
- 6823932
- Journal Information:
- Phys. Rev. A; (United States), Journal Name: Phys. Rev. A; (United States) Vol. 35:2; ISSN PLRAA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Molecular & Chemical Physics-- Beams & their Reactions
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ADSORPTION
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
COLLISIONS
CROSS SECTIONS
ELECTRON COLLISIONS
ELECTRON SPECTROSCOPY
ELEMENTS
ENERGY
ENERGY RESOLUTION
ENERGY-LEVEL TRANSITIONS
ENERGY-LOSS SPECTROSCOPY
EXCITATION
METALS
NITROGEN
NONMETALS
OXIDES
OXYGEN COMPOUNDS
RESOLUTION
SORPTION
SPECTROSCOPY
THRESHOLD ENERGY