Results 211 to 220 of about 494,691 (265)
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Applied Physics, 1978
From positron annihilation lifetime measurements on V3Si single crystals we estimated that about 17.2% of the positrons annihilate with core electrons.
G. Brauer, A. Balogh, A. Andreeff
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From positron annihilation lifetime measurements on V3Si single crystals we estimated that about 17.2% of the positrons annihilate with core electrons.
G. Brauer, A. Balogh, A. Andreeff
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On positron lifetime in anthracene
Il Nuovo Cimento, 1959The decay times of positrons were measured in anthracene in the range - 200 to 295 deg C. The lifetime in solid anthracene was (3.7 plus or minus 0.2) x 10/sup -10/s. Above the melting point the value was 2.3 x 10/sup -9/s. (C.J.G.)
C. Cottini +3 more
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THE LIFETIMES OF POSITRONS IN METALS
Canadian Journal of Physics, 1961The lifetimes of positrons annihilating in some 21 metals have been measured comparatively with the lifetime in aluminum. Significant variations have been found, as large as 30% of the absolute lifetime in aluminum, and the lifetime shows a more marked dependence on the atomic density than on the valence electron density of the metal. By comparison of
G. Jones, J. B. Warren
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Journal of the Physical Society of Japan, 1972
Lifetime spectra of positrons is oxides were measured. Densities of oxygen ions corrected for the ionicities are rather good parameters describing τ 1 -1 and thus positrons may be itinerant in oxides. The annihilation rates τ 1 -1 are about 1.5 times as large as those which are calculated on the assumption that the positrons distribute homogeneously.
Masayasu Noguchi +4 more
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Lifetime spectra of positrons is oxides were measured. Densities of oxygen ions corrected for the ionicities are rather good parameters describing τ 1 -1 and thus positrons may be itinerant in oxides. The annihilation rates τ 1 -1 are about 1.5 times as large as those which are calculated on the assumption that the positrons distribute homogeneously.
Masayasu Noguchi +4 more
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Lifetime Measurements with a Scanning Positron Microscope
Physical Review Letters, 2001Physical Review ...
A, David +3 more
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Lifetimes of positrons trapped at Si vacancies
Physical Review B, 1996We present first-principles calculations on positron lifetimes at various vacancies in Si. Lattice relaxation and electron redistribution caused by the vacancy and by the positron are included using the two-component density-functional theory. The calculated lifetimes are in agreement with the experimental data for the monovacancies and the divacancies
, Saito, , Oshiyama
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Positron lifetimes in strongly deformed metals
Physica Status Solidi (a), 1973The influence of dislocations on the positron lifetime and lineshape S-factor is observed for Mg, Al, Cd, Sn, Pt, Au, Cu, and Ni. A strong increase of the lifetime is found in the deformed specimen except for Sn, Cd, and Mg. An analysis method for the exponential decay curves is discussed.
Ch. Dauwe +3 more
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Positron lifetime in inhomogeneous metallic materials
Crystal Research and Technology, 1987AbstractA positron is considered in an inhomogeneous jellium model according to a formalism following from the theory of liquids. This leads to a nonlocal treatment of the screening of this particle. Annihilation rates have been found inferior to the ones for a homogeneous electron gas, in agreement with positron lifetime measurements.
J Gondzik, H Stachowlak
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Positron distributions and lifetimes in novel superconductors
Journal of Physics and Chemistry of Solids, 1993Abstract We have calculated positron distributions and lifetimes in novel superconductors and related materials using the superposed-atom model and the numerical relaxation technique. Both delocalized and trapped states of positrons are investigated for infinite-layer compound SrCuO 2 and alkali-or alkaline-earth-doped C 60 .
Ishibashi S. +5 more
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Positron lifetimes in metal hydrides
Il Nuovo Cimento B Series 10, 1968Positron-decay curves in commercially available metal hydrides have been measured, using a delayed coincidence system with 0.37 ns (FWHM) prompt time resolution. Evidence was found that the annihilation is complex, with two exponential decays of comparable intensities.
A. GAINOTTI +3 more
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