Line profile of H Lyman-{beta} emission from dissociative excitation of H{sub 2}

Journal Article · Mon Apr 01 04:00:00 EST 1996 · Physical Review A

DOI:https://doi.org/10.1103/PhysRevA.53.2303· OSTI ID:279914

Ajello, J M; Ahmed, S M; Liu, X ^[1]

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1. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States)

A high-resolution ultraviolet spectrometer was employed for a measurement of the H Lyman-{beta} (H L{sub {beta}}) emission Doppler line profile at 1025.7 A from dissociative excitation of H{sub 2} by electron impact. Analysis of the deconvolved line profile reveals the existence of a narrow central peak, less than 30 mA full width at half maximum (FWHM), and a broad pedestal base about 260 mA FWHM. Analysis of the red wing of the line profile is complicated by a group of Werner and Lyman rotational lines 160{endash}220 mA from the line center. Analysis of the blue wing of the line profile gives the kinetic-energy distribution. There are two main kinetic-energy components to the H(3{ital p}) distribution: (1) a slow distribution with a peak value near 0 eV from singly excited states, and (2) a fast distribution with a peak contribution near 7 eV from doubly excited states. Using two different techniques, the absolute cross section of H L{sub {beta}} is found to be 3.2{plus_minus}0.8{times}10{sup {minus}19} cm{sup 2} at 100-eV electron impact energy. The experimental cross-section and line-profile results can be compared to previous studies of H{alpha} (6563.7 A) for principal quantum number {ital n}=3 and L{sub {alpha}} (1215.7 A) for {ital n}=2. {copyright} {ital 1996 The American Physical Society.}

• OSTI ID: 279914
• Journal Information: Physical Review A, Journal Name: Physical Review A Journal Issue: 4 Vol. 53; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BALMER LINES
DISSOCIATION
DOPPLER EFFECT
ELECTRON-MOLECULE COLLISIONS
EV RANGE 10-100
EXCITED STATES
FLUORESCENCE
HYDROGEN
KINETIC ENERGY
LINE SHAPE
LINE WIDTHS
LYMAN LINES
ULTRAVIOLET SPECTRA