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Abstract: Odd-mass isotopic chain of 67–79As has been studied within the context of the projected shell model. Deformed single-particle states generated by the standard Nilsson potential are used to calculate various nuclear structure properties like yrast spectra, rotational frequencies and reduced transition probabilities. The study of band structures of these As nuclei based on the band diagrams indicates the presence of multi-quasiparticle structure in the high spin realm of these nuclei. Rotational alignment phenomenon has also been studied in terms of band crossing which is understood to occur due to the rotational alignment of neutron pair. We also have compared the results of the present calculations with the available experimental as well as the other theoretical data and an overall good agreement has been achieved between the two. [Copyright &y& Elsevier]

Abstract: Full shell-model diagonalization has been performed to study the structure of neutron-rich nuclei around 20C. We investigate in detail the roles played by the different monopole components of the effective interaction in the evolution of the shell in C, N and O isotopes. It is found that the relevant neutron–neutron monopole terms, and , contribute significantly to the reduction of the shell gap in C and N isotopes in comparison with that in O isotopes. The origin of this unexpectedly large effect, which is comparable with (sometimes even larger than) that caused by the proton–neutron interaction, is related to the enhanced configuration mixing in those nuclei due to many-body correlations. Such a scheme is also supported by the large value in the nucleus 20C which has been measured recently. [Copyright &y& Elsevier]

Abstract: In this plenary talk, we will overview the evolution of the shell structure in stable and exotic nuclei as a new paradigm of nuclear structure physics. This shell evolution is primarily due to the tensor force. The robust mechanism and some examples will be presented. Such examples include the disappearance of existing magic numbers and the appearance of new ones. The nuclear magic numbers have been believed, since Mayer and Jensen, to be constants as 2, 8, 20, 28, 50, …This turned out to be changed, once we entered the regime of exotic nuclei. This shell evolution develops at many places on the nuclear chart in various forms. For example, superheavy magic numbers may be altered. Thus, we are led to a new paradigm as to how and where the nuclear shell evolves, and what consequences arise. The evolution of the shell affects weak process transitions, and plays a crucial role in deformation. The π and ρ mesons generate tensor forces, and are the fundamental elements of such intriguing phenomena. Thus, physics of exotic nuclei arises as a manifestation of Yukawa''s forces. [Copyright &y& Elsevier]