[en] This paper is divided into three broad categories: Spin Physics in Nuclei; Surprising Near Degeneracies; and Incompressibility, Isotope Shifts and Breathing Mode States

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[en] The summed strength for transitions from the ground state of ¹²C via the operators st, lt, rY¹t, r[Y¹s]^λt and r[Y¹λ]^λt are calculated using the ΔN = 0 rotational model. If we choose the z-component of the isospin operator t_z, the above operators are relevant to electromagnetic transitions; if we choose t₊, they are relevant to weak transitions such as neutrino capture. In going from the spherical limit to the asymptotic (oblate) limit the strength for the operator st decreases steadily to zero; the strength for the operator λt (scissors mode) increases by a factor of three. For the last three operators, isovector dipole, spin dipole and orbital dipole (including the twist mode), it is shown that the summed strength is independent of deformation. The main difference in the behavior is that for the first two operators we have in-shell transitions whereas for the last three operators the transitions are out of shell

[en] It was shown by Blomqvist and Molinari and by Millener and Kurath that the difference in energy (ΔE) between the Jπ =0^-, T=1 and T=0 1p-1h states in ¹⁶O is due mainly (but not exclusively) to the tensor interaction, The dominant configuration is (1s_1/20p_1/2^-1)^0- with a small admixture of (0d_3/20p_3/2-1)^0-. With a bare open-quotes realisticclose quotes Bonn A interaction, the value of ΔE is 3.08 MeV, significantly larger than the experimental value of 1.845 MeV. A naive analysis would lead to the conclusion that the tensor interaction in the nucleus is too strong. However. in second-order perturbation theory, the value of ΔE decreases from about 3 MeV to about 2 MeV in closer agreement with experiment, i.e., the second-order contribution is -1 MeV. It is further shown that the tensor interaction plays a vital role in making the second-order contribution significant. The second-order contribution is due to the exchange of a 2hω positive-parity phonon between the original particle and hole. For a closed LS shell, the tensor interaction cannot contribute to the coupling of a particle to a monopole (J=0) phonon. The magnetic dipole (J=1) and other (J > 1) phonons are therefore important

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[en] This chapter attempts to justify the study of large nuclei by showing, for example, that the double beta decay process is enhanced in large nuclei where pairing correlations are important. Discusses shell model calculation; more than two particles in the f /sub 7/2/ shell; neutrons and protons in the f /sub 7/2/ shell; application to magnetic moments; spectroscopic strengths; single beta decay; double beta decay; the K selection rule of Lawson; double beta decay in heavier nuclei; coherent pairing effects; the effect of delta particle-nucleon hole admixtures on double beta decay; giant resonances; soluble model-monopole-monopole interaction; core polarization with the monopole-monopole interaction; isoscalar quadrupole resonances; schematic vs. delta interaction-degenerate model; Skyrme interaction for the isoscalar quadrupole state (also isoscalar); spin dependent models; higher order effects in core polarization; and E6 suppression (open shell nucleus effect?). Demonstrates that open shell effects can be very important and that they should be thoroughly investigated before more exotic mechanisms are proposed

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