Kinetic-energy distribution of D(2p) atoms from analysis of the D Lyman-{alpha} line profile
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States)
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80303 (United States)
The kinetic-energy distribution of D(2p) atoms resulting from electron-impact dissociation of D{sub 2} has been measured. A high-resolution vacuum ultraviolet spectrometer was employed for the first measurement of the D Lyman-{alpha} (D L{alpha}) emission line profiles at 20- and 100-eV excitation energies. Analysis of the deconvoluted line profile of D L{alpha} at 100 eV reveals the existence of a narrow line central peak of 29{plus_minus}2m{Angstrom} full width at half maximum and a broad pedestal wing structure about 190 m{Angstrom} wide. The wings of the line can be used to determine the fast atom distribution. The wings of D L{alpha} arise from dissociative excitation of a series of doubly excited states that cross the Franck-Condon region between 23 and 40 eV. The fast atom distribution at 100-eV electron impact energy spans the energy range from 1 to 10 eV with a peak value near 6 eV. Slow D(2p) atoms characterized by a distribution function with peak energy near 100 meV produce the central peak profile, which is nearly independent of the impact energy. The deconvoluted line profiles of the central peak at 20 eV for dissociative excitation of D{sub 2} and H{sub 2} are fitted with an analytical function for use in calibration of space flight instrumentation equipped with a D/H absorption cell. The kinetic-energy and line profile results are compared to similar measurements for H{sub 2}. The absolute cross sections for the line center (slow atoms) and wings (fast atoms) and total emission line profile were measured from threshold to 400 eV. Analytical model coefficients are given for the energy dependence of the measured slow atom cross section. {copyright} {ital 1997} {ital The American Physical Society}
- OSTI ID:
- 538502
- Journal Information:
- Physical Review A, Journal Name: Physical Review A Journal Issue: 3 Vol. 56; ISSN 1050-2947; ISSN PLRAAN
- Country of Publication:
- United States
- Language:
- English
Similar Records
Line profile of H Lyman-{beta} emission from dissociative excitation of H{sub 2}
Kinetic-energy distribution of excited atoms produced when H/sub 2/ and D/sub 2/ molecules are dissociated by electron impact
Dissociative excitation of H$sub 2$: Spectral line shapes and electron impact cross sections of the Balmer lines
Journal Article
·
Sun Mar 31 23:00:00 EST 1996
· Physical Review A
·
OSTI ID:279914
Kinetic-energy distribution of excited atoms produced when H/sub 2/ and D/sub 2/ molecules are dissociated by electron impact
Journal Article
·
Wed Nov 30 23:00:00 EST 1977
· Sov. Phys. - JETP (Engl. Transl.); (United States)
·
OSTI ID:6687069
Dissociative excitation of H$sub 2$: Spectral line shapes and electron impact cross sections of the Balmer lines
Journal Article
·
Sat Jan 31 23:00:00 EST 1976
· J. Chem. Phys., v. 64, no. 3, pp. 1122-1127
·
OSTI ID:4035939