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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 10 (1976), S. 67-79 
    ISSN: 1432-0630
    Keywords: 78.70
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The theories regarding the formation of positronium in molecular substances are discussed. A modified theory based upon the “spur” theory is described. Theoretical derivation and experimental results suggest that the fraction of the long lifetime component due too-positronium annihilation has a complex origin. Initially, the electron of the positron-electron pair is likely to be separated from the positron by medium molecules even when the total kinetic energy of the pair is less than the potential energy between them. The formation of positronium depends on the mobilities of the positron and electron, the slowing down process and the potential energy between them. Positronium is formed in less than 10 ps. Then the positronium produced may react with the radicals created in the “spur” due to the positron. Only the fraction ofo-positronium able to escape the “spur” will have a long lifetime. Therefore, positronium formation is highly related to the fast reactions in the “spur” during the first 100 ps.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 11 (1976), S. 247-251 
    ISSN: 1432-0630
    Keywords: 78.70
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Positron annihilation in nitrobenzene and manganese oleate solutions in benzene was studied in the liquid and solid states using both lifetime and angular correlation methods. It was found that a long lifetime component (τ2~1.3 ns) appeared in the lifetime spectrum for the solid state of a nitrobenzene solution in benzene but not in the liquid state. The results are briefly discussed.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 16 (1978), S. 409-411 
    ISSN: 1432-0630
    Keywords: 29 ; 02 ; 71
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The relationship between some popularly used arbitrary parameters and the variance of the Doppler broadening spectra of positron annihilation γ-rays is discussed. The experimental results are found to agree well with the theoretically derived formulas.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Macromolecules 10 (1977), S. 713-715 
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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