Volume 17, Issue 5
November 1981, pages 369-443
pp 369-380 November 1981 Nuclear And Particle Physics
The odd-proton nucleus155Tb and odd-neutron nucleus155Dy are studied along with doubly-even nucleus156Dy using microscopic method of variation after projection of angular momentum and conservation of nucleon number in each projected state. The calculated energies of the ground band in156Dy and the ground and excited bands in155Dy and155Tb are in good agreement with the corresponding experimental data. The role played by thei13/2 neutron pair in these nuclei is discussed.
pp 381-387 November 1981 Nuclear And Particle Physics
The effect of including the high spin bosons on the manifestation of collective behaviour in nuclei is examined by plotting theB(E2; 2+→0+) rates as a function of neutron number for various values ofη, whereη is the highest angular momentum of the bosons included in the calculation.B(E2; 2+→0+) values of a large number of nuclei in various regions of the nuclear periodic table are calculated with a single value for the effective charge in the generalized scheme. Irreducible representations of SU(3) contained in the symmetric partition [N] of U(15) are worked out for integersN uptoN=15, to enable the explicit inclusion of theg boson into calculations. The experimentally observed odd-K bands in234U and184W are described as a direct consequence of theg boson.
pp 389-393 November 1981 Nuclear And Particle Physics
The influence of chromomagnetic hyperfine interaction onB andT hadrons is studied. The colour magnetic moments are related to the hyperfine splittings of hadrons.
pp 395-404 November 1981 Nuclear And Particle Physics
We investigate the asymmetries arising due to electromagnetic interactions in largePT pion inclusive processes. The hardqcd processes that contribute to such asymmetries areq+g→q+γ,q+q→g+γ etc. which are suspected to be substantial, as indicated by theqcd predictions for a significant and increasingγ/πo ratio at largePT. We calculate the expected isospin related asymmetries and propose tests that might detect them. Our estimates indicate that the effects are much smaller than may be naively expected. We also observe a remarkable scaling of asymmetries in the variablePT/(s)1/2.
pp 405-414 November 1981 Nuclear And Particle Physics
We consider the effects ofη−π mixing on the violation of the |ΔI|=1/2 rule in |ΔS|=1 weak transitions. The processes considered are theK→2π,K→3π, Λ, Ξ and Λ hyperon decays.
pp 415-418 November 1981 Solid State Physics
Cottrell’s binding energy between a dislocation and vacancy and concentration of vacancies has been calculated using ultrasonic attenuation measurements in single crystals of pure tin at 300K for frequencies varying from 3 to 50 MHz and at different dislocation densities.
pp 419-427 November 1981 Solid State Physics
Unified study of the different properties of metals clearly reveals the inadequacy of the empty-core Ashcroft pseudopotential even in the case of simple metals. In the present paper we propose a modification of the one-parameter Ashcroft pseudopotential by assuming the parameterrc to be wave vector-dependent. This introduces a simple modification of the electron-ion pseudopotential in the reciprocal space. The corresponding potential in the configuration space shows that the abrupt change in the Coulomb potential atr=rc is replaced by a continuous change spread over a small region near the core boundary. The present model has been used to make a unified study of Al and is found to be a significant improvement over the simple Ashcroft model. The agreement between the calculated and experimental values is found to be quite satisfactory.
pp 429-442 November 1981 Solid State Physics
ZnS:Gd, ZnS: Cu, Gd and ZnS: Mn, Gd phosphors have been prepared by firing the samples in argon atmosphere. Spectral distributions in these phosphors are discussed with appropriate mechanism. ZnS:Cu, Gd and ZnS:Mn, Gd are found to be examples of multiple band phosphors. Enhancement and quenching of the emission band intensities of all these phosphors have been studied inpel emission. It is observed that Gd3+ ions play an important role in transferring their excitation energy to other centres. The voltage and frequency variation ofel brightness are in agreement with collision excitation mechanism in Schottky barrier at the metal semiconductor interface. Studies in phosphorescence and thermoluminescence of these phosphors have also been carried out. It is observed that trap-depth changes slowly with temperature and dopant concentration. The values of trapping parameters have been evaluated. The irregular variation of the life-time of electrons in the traps. with temperature shows the existence of retrapping in these phosphors.
pp 443-443 November 1981 Erratum
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