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Title: Generalized oscillator strengths. Progress report, July 1, 1974--July 1, 1975

Authors:
Publication Date:
Research Org.:
Carnegie-Mellon Univ., Pittsburgh, Pa. (USA)
Sponsoring Org.:
US Energy Research and Development Administration (ERDA)
OSTI Identifier:
4234464
Report Number(s):
COO-3247-29
NSA Number:
NSA-32-005821
DOE Contract Number:
AT(11-1)-3247
Resource Type:
Technical Report
Resource Relation:
Other Information: Orig. Receipt Date: 31-DEC-75
Country of Publication:
United States
Language:
English
Subject:
N80740* -General & Miscellaneous-Physics & Engineering; *CARBON DIOXIDE- ENERGY LEVELS; *NITROGEN- ENERGY SPECTRA; *WATER- ENERGY LEVELS; BOUNDARY CONDITIONS; CROSS SECTIONS; ELECTRONS; ENERGY; ENERGY- LEVEL TRANSITIONS; EV RANGE 100-1000; EXCITATION; HELIUM; KINETIC ENERGY; OSCILLATOR STRENGTHS; RESEARCH PROGRAMS

Citation Formats

Lassettre, Edwin N. Generalized oscillator strengths. Progress report, July 1, 1974--July 1, 1975. United States: N. p., 1975. Web. doi:10.2172/4234464.
Lassettre, Edwin N. Generalized oscillator strengths. Progress report, July 1, 1974--July 1, 1975. United States. doi:10.2172/4234464.
Lassettre, Edwin N. Wed . "Generalized oscillator strengths. Progress report, July 1, 1974--July 1, 1975". United States. doi:10.2172/4234464. https://www.osti.gov/servlets/purl/4234464.
@article{osti_4234464,
title = {Generalized oscillator strengths. Progress report, July 1, 1974--July 1, 1975},
author = {Lassettre, Edwin N.},
abstractNote = {},
doi = {10.2172/4234464},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Jan 01 00:00:00 EST 1975},
month = {Wed Jan 01 00:00:00 EST 1975}
}

Technical Report:

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  • Progress is described on research under Contract AT(11-1)3247 and research still to be completed in the period July 1, 1973 to July 1, 1974. The research objectives defined in the original proposal were closely followed. The principal accomplishments during the period were: The introduction of a computer controlled counting system with provision for automatic control and operation of the electron spectrometer currently in use. Electron scattering with excitation of singlet-triplet transitions for helium was studied during the year both to acquire information on collision cross sections and to test a general theory of the abnormally high cross sections for forwardmore » scattering found for certain types of transitions. A theoretically predicted minimum in the cross section (at zero scattering angle) was found in a study over the range 100 to 500 eV of the 1/sup 1/S yields 2/sup 3/S transition of helium. Abnormally high cross sections for singlet-triplet transitions at high kinetic energy are predicted when the orbital term symbol is unchanged on excitation. As a test of the theory the X/sup 1/ SIGMA /sup +/ yields b/sup 3/ SIGMA /su p +/ transition in CO was looked for and found at THETA = 0 deg at both 200 and 300 eV thus confirming the theory. New electron scattering studies on both CO and CO/sub 2/ are described. A new method for the calculation of singlet-triplet energy differences from generalized oscillator strengths is described. (auth)« less
  • Collision cross section determinations on the transition E/sup 3/ ..sigma../sup +//sub g/ reversible arrow X/sup 1/ ..sigma../sup +//sub g/ in N/sub 2/ at 100, 200, and 300 eV show that the cross section decreases steadily at each kinetic energy as the scattering angle increases at angles in the range 2/sup 0/ ..-->.. 14/sup 0/. Thus, the transition resembles the 2/sup 3/S reversible arrow 1/sup 2/S transition helium studied by Dillon (J. Chem. Phys. 63, 2035 (1975)). Both singlet-triplet transitions belong to a class for which the cross section is abnormally high in forward scattering as expected, since the orbital termmore » symbol is the same in ground and excited states. The study of the singlet-triplet transition in N/sub 2/ is reported. Two theoretical studies have been completed, one on the functional form at one-electron momentum distributions deduced from a local one-electron potential function, and the second on the connection between generalized oscillator strengths and collision cross sections (in Born approximation) for resonant energy transfer in the collision of two molecules.« less
  • Progress in the study of generalized oscillator strengths since January 1, 1970 is reviewed. The status of methods for the experimental determination of electron collision cross sections and generalized oscillator strengths is discussed including the comparison of inelastic and elastic scattering when elastic cross sections are available, the use of a comparison gas with a transition of known cross section, and the determination of optical oscillator strengths from forward scattering spectra. Outstanding discrepancies between limiting generalized oscillator strengths (at zero momentum change) and optical oscillator strengths are resolved for the most part. There are no longer any outstanding discrepancies involvingmore » refractive indices. Two new selection rules, one relating to singlet-singlet transitions, the other to singlet-triplet transitions are described. Other deviations from the Born approximation at large momentum changes are discussed. Generalized oscillator strengths are applied to the calculation of cross sections (in Born approximation) for resonant energy transfer in collision between two molecules one of which is excited. A list of publications is included.« less
  • Progress in the study of generalized oscillator strengths since January 1, 1970 is reviewed. The status of methods for the experimental determination of electron collision cross sections and generalized oscillator strengths is discussed including the comparison of inelastic and elastic scattering when elastic cross sections are available, the use of a comparison gas with a transition of known cross section, and the determination of optical oscillator strengths from forward scattering spectra. Outstanding discrepancies between limiting generalized oscillator strengths (at zero momentum change) and optical oscillator strengths are resolved for the most part. There are no longer any outstanding discrepancies involvingmore » refractive indices. Two new selection rules, one relating to singlet-singlet transitions, the other to singlet-triplet transitions are described. Other deviations from the Born approximation at large momentum changes are discussed. Generalized oscillator strengths are applied to the calculation of cross sections (in Born approximation) for resonant energy transfer in collision between two molecules one of which is excited. A list of publications is included.« less
  • Progress is reported on studies on the role of auxin in plant cell elongation. Biochemical reactions in Avena (oats) coleoptiles are discussed. (CH)