Study of nuclear structure of some nuclei in medium mass region

Abstract

This research work is limited to the medium mass region (A=150-200). In this work, the collective nuclear structures of some medium mass nuclei have been analyzed, using empirical studies, phenomenological, geometrical, group theoretical models. The research work is divided into five Chapters. The Introduction is given in the Chapter I and Nuclear Models are discussed in Chapter II. In Chapter III, the values of asymmetry parameter (and#947;0) of Davydov and Filippov model are calculated using the experimental energies of E22+ and E21+ states for 50and#8804;Zand#8804;82 and 82and#8804;Nand#8804;126 region. The whole calculated data is divided into four quadrants. The Quadrant I (Q-I) is for 50and#8804;Zand#8804;66 and 82and#8804;Nand#8804;104 shell space with particle like proton-bosons and neutron-bosons and it is forming the p-p space. The Quadrant II (Q-II) is for 66and#8804;Zand#8804;82 and 82and#8804;Nand#8804;104 shell space, with hole like proton-bosons space and particle like neutron-bosons space and it is forming the h-p space. The Quadrant III (Q-III) is for 66and#8804;Zand#8804;82 and 104and#8804;Nand#8804;126 region shell space, with hole like proton-bosons and neutron-bosons and it is forming h-h space. The quadrant IV (Q-IV) is for 50and#8804;Zand#8804;66 and 104and#8804;Nand#8804;126 shell space with particle like proton-bosons and hole like neutron-bosons and it is forming the p-h space. The study of systematic dependence of and#947;0 on N, NB and NpNn has been carried out on quadrant wise basis to find out the role of valence nucleons and holes on the nuclear structure. The role of Z=64 subshell effect for Nand#8804;90 region is also discussed. The NpNn product is a good measure of its effect in producing the deformation in atomic nuclei. This product is also an indicator of the n-p interaction among the valance proton and/or neutron nucleons causing the deformation of nuclear core. In quadrant-I and quadrant-II, the asymmetry parameter decreases; from 300 in Q-I and from 220 in Q-II to 90- 100; with increasing N from 82 to 104 (i.e. the mid of N=82 to 126 neutron shell), signifying that the nuclear deformation (and#946;) is increasing, while the energy ratio R4 increases from 2 (f