Angular correlation of two-photon positron annihilation in molecular hydrogen and nitrogen

1994 ◽  
Vol 89 (1) ◽  
pp. 319-324 ◽  
Author(s):  
A. S. Ghosh ◽  
T. Mukherjee ◽  
J. W. Darewych
Keyword(s):  
Positron Annihilation ◽  
Angular Correlation ◽  
Molecular Hydrogen ◽  
Two Photon

Two-photon momentum density and angular correlation of positron annihilation radiation in Pd and PdH

1986 ◽  
Vol 34 (2) ◽  
pp. 853-858 ◽  
Author(s):  
Anjali Kshirsagar ◽  
D. G. Kanhere ◽  
R. M. Singru
Keyword(s):  
Positron Annihilation ◽  
Angular Correlation ◽  
Momentum Density ◽  
Annihilation Radiation ◽  
Photon Momentum ◽  
Two Photon

Positron annihilation in oriented single crystals of calcite: Two photon angular correlation

1980 ◽  
Vol 15 (1) ◽  
pp. 115-120
Author(s):  
P. Ramasamy ◽  
F. D. Gnanam ◽  
S. Krishnan ◽  
G. S. Laddha
Keyword(s):  
Single Crystals ◽  
Positron Annihilation ◽  
Angular Correlation ◽  
Two Photon

MOMENTUM DISTRIBUTIONS OF TWO PHOTON ANNIHILATING POSITRON–ELECTRON PAIRS IN HEXANE AND DECANE

1967 ◽  
Vol 45 (12) ◽  
pp. 3895-3900 ◽  
Author(s):  
S. Y. Chuang ◽  
B. G. Hogg
Keyword(s):  
Wave Function ◽  
Positron Annihilation ◽  
Angular Correlation ◽  
High Precision ◽  
Atomic Carbon ◽  
Electron Pairs ◽  
Two Photon ◽  
Momentum Distributions ◽  
Positron Wave Function

Momentum distributions are calculated for electrons in the C–C and C–H bonds in hydrocarbons, using analytic SCF functions for atomic carbon orbitals and Heitler–London-type functions for the two paired electrons in the C–C and C–H bonds. The positron wave function is assumed to be a constant. The computed momentum distributions are then compared with high-precision experimental distributions obtained from positron-annihilation angular correlation experiments.

Angular correlation of two-photon positron annihilation in hydrogen gas

1979 ◽  
Vol 57 (7) ◽  
pp. 1027-1030 ◽  
Author(s):  
J. W. Darewych
Keyword(s):  
Wave Function ◽  
Angular Correlation ◽  
Molecular Hydrogen ◽  
Hydrogen Gas ◽  
Annihilation Radiation ◽  
Annihilation Rate ◽  
Two Photon ◽  
State Approximation ◽  
The One ◽  
Photon Annihilation

The expression for the angular correlation of two-photon annihilation radiation for positrons colliding with molecular hydrogen is derived. The one-state approximation is used, and a one-centre expansion of the hydrogen wave function is assumed. Results obtained using a simple H2 wave function yield a half-width of the angular distribution which is in agreement with the observed results for positrons annihilating in liquid hydrogen. Comparison is made with corresponding results for the annihilation rate.

Positron Annihilation with Core Electrons in the Noble Metals

1974 ◽  
Vol 52 (4) ◽  
pp. 336-339 ◽  
Author(s):  
E. H. Becker ◽  
A. G. Gould ◽  
E. M. D. Senicki ◽  
B. G. Hogg
Keyword(s):  
Simple Model ◽  
Fermi Surface ◽  
Single Crystals ◽  
Positron Annihilation ◽  
Angular Correlation ◽  
Noble Metals ◽  
Correlation Data ◽  
Core Electrons

Experimental angular correlation curves for identically oriented single crystals of copper, silver, and gold have been obtained using "a point geometry" apparatus. The differences between these angular correlation data are compared to the differences predicted using a simple model of the Fermi surface combined with calculations of the theoretical core distributions.

Investigation of Polymer Relaxation after Deformation by Positron Annihilation

1992 ◽  
Vol 247 ◽  
Author(s):  
Sergey A. Tishin ◽  
Mihail I. Tsapovestsky ◽  
Vladimir A. Tishin ◽  
Vladimir N. Kestelman
Keyword(s):  
Positron Annihilation ◽  
Angular Correlation ◽  
Life Time ◽  
Slow Relaxation ◽  
Dielectric Losses ◽  
Free Film ◽  
Axial Tension ◽  
Polymer Relaxation ◽  
Sample Density ◽  
Nonmonotonic Change

ABSTRACTThe relaxation of polyimid films after the axial tension has been investigated by measuring life-time of positrons and angular correlation of annihilation photons. The nonmonotonic change of mean life-time while relaxing the free film has been found. Two range of changes of positron-sensitive properties can be seen: “rapid” relaxation for 4–5 hours (characterized by reducing life-time of short-lived component) and “slow” relaxation (characterized by reducing the intensity of long-lived component). The results of this investigation have been compared with those of measuring of sample density and dielectric losses. The possible explanations and the- changes of mechanizms of relaxation with the conditions of deformation and “the rest” of polymers are analyzed.

Angular correlation of positron annihilation radiation from solid and liquid bismuth and mercury and a bismuth-mercury alloy

1967 ◽  
Vol 92 (1) ◽  
pp. 195-205 ◽  
Author(s):  
R N West ◽  
R E Borland ◽  
J R A Cooper ◽  
N E Cusack
Keyword(s):  
Positron Annihilation ◽  
Angular Correlation ◽  
Annihilation Radiation ◽  
Liquid Bismuth

Angular Correlation of Positron Annihilation Radiation from Single Crystals of Vanadium-Deuterium Alloys

1979 ◽  
Vol 46 (2) ◽  
pp. 481-487 ◽  
Author(s):  
Masayuki Hasegawa ◽  
Shu-ichi Koike ◽  
Makoto Hirabayashi ◽  
Hajime Asano ◽  
Toshiharu Suzuki
Keyword(s):  
Single Crystals ◽  
Positron Annihilation ◽  
Angular Correlation ◽  
Annihilation Radiation
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