High-Rydberg atomic fragments from electron-impact dissociation of molecules

Journal Article · Tue May 15 04:00:00 EDT 1979 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.437283· OSTI ID:6284299

Schiavone, J A; Tarr, S M; Freund, R S

The production of high-Rydberg (HR) atomic fragments by electron-impact dissociation of 13 molecules has been compared to the results of previous work on the production of HR rare gas atoms. Measurements have been made of principal quantum number distributions, effective radiative lifetimes, and excitation cross sections including both the shapes as a function of electron-impact energy and the absolute magnitudes. Principal quantum number (n) distributions peak at lower n values than those for the rare gases and are consistent with the shorter times of flight of dissociation fragments. The HR atomic fragments appear to form in high angular momentum (l) states as a direct result of the dissociation process, whereas rare gas atoms form initially in low-l HR states and require subsequent electron collisions to reach high-l HR states. The energy dependence of the excitation cross sections, a slow rise from threshold with a peak near 100 eV, resembles that of other dissociative excitation processes and does not display the step function threshold characteristic of the rare gases. Magnitudes of the excitation cross sections are expressed in a form which separates the apparatus-dependent radiative decay factor from the initial excitation cross section. The result permits calculation of HR densities under a variety of electron-impact dominated conditions.

• Research Organization: Bell Laboratories, Murray Hill, New Jersey 07974
• OSTI ID: 6284299
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 70:10; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ALKANES
ALKENES
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
COLLISIONS
CROSS SECTIONS
CRYOGENIC FLUIDS
DEUTERIUM
DISSOCIATION
ELECTRON COLLISIONS
ELECTRON-MOLECULE COLLISIONS
ELEMENTS
ETHANE
FLUIDS
HEXANE
HYDROCARBONS
HYDROGEN
HYDROGEN ISOTOPES
ISOTOPES
LIFETIME
LIGHT NUCLEI
METHANE
MOLECULE COLLISIONS
NITROGEN
NONMETALS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PROPANE
QUANTUM NUMBERS
STABLE ISOTOPES