ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
Formation of an excited hydrogen atom (H*) through electron-impact dissociation of ethylene has been investigated by measuring Doppler profiles of the Balmer-β line and their angular dependence at an optical resolution of 0.007 nm. The Doppler profiles show a clear anisotropy. The translational energy distribution (TED) and the angular difference Doppler profile were obtained. There are four major dissociation processes for the formation of H*(n=4). Component 1 has a peak of TED at 1 eV, is produced in a perpendicular distribution, and should be produced by predissociation through the Rydberg states converging to the (1b1u)−1 state. Component 2 has a peak of TED at 1.8 eV, is produced in a parallel distribution, and should be produced through the Rydberg states converging to the (2ag)−1 state. Component 3 has a peak of TED at 2–6 eV and is produced in a parallel distribution. Component 4 has a peak of TED at 5–10 eV. Molecular orientation at the time of excitation was estimated; the molecular plane is perpendicular to the electron beam for component 1, and the C=C bond is perpendicular and the molecular plane is parallel to the electron beam for components 2 and 3. The asymmetry parameters of components 2 and 3 were ≤0.2; these values were much smaller than anticipated due largely to molecular rotation and deformation at the time of dissociation.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.463689
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