Nuclear Data Sheets for A = 152

Electric monopole transitions between 0+ states for nuclei throughout the periodic table

Quadrupole collective properties of 114Cd

Studies of the structure and decay modes of nuclei far from stability have yielded many new insights which were not seen in nuclei near the line of beta stability. The results of recent experimental and theoretical investigations are presented and the new insights being gained are discussed. Some of the highlights described include ground-state proton radioactivity, beta -delayed 2n, 3n and 2p decays, the coexistence of states built on quite different nuclear shapes in the same nucleus, new regions of strongly deformed nuclei, and the importance of the reinforcement of proton and neutron shell gaps on the shape of a nucleus.

Advances in studies of nuclei far from stability

The present review deals with nuclear models which consider collective proton and neutron motion separately in terms of bosons. Extensions of the geometric Bohr-Mottelson model are sketched, followed by a more extensive discussion of the algebraic interacting boson approximation (IBA-2). In the latter the concept of F spin plays a central role, and detailed attention is paid to its tensorial properties. A general projection method is presented whereby any IBA-2 calculation for states of maximal F spin can be transformed into a simpler one in IBA-1, where the proton-neutron distinction is ignored. Data are presented on F-spin multiplets, and global fits with the IBA are discussed. A major portion of the review is concerned with M1 transitions. Strong M1s in deformed and spherical nuclei, with emphasis on the latter, are discussed as resulting from a change in proton-neutron symmetry. Weak M1s are considered as reflecting such symmetry changes in small amplitudes of the wave function. Attention is given to one-fluid boson models (IBA-1, geometric) simulating these two-fluid effects.

https://iopscience.iop.org/article/10.1088/0034-4885/53/11/001/pdf

Proton-neutron symmetry in boson models of nuclear structure

Measurements of E2/M1 and E0/E2 multipole mixing ratios of transitions in even-even nuclei have long provided important tests of nuclear models. The experimental data for transitions in even-even nuclei have been critically surveyed to provide the most accurate results for comparisons with theoretical calculations. The theoretical approaches to the calculations of these mixing ratios on the bases of different nuclear models are considered and compared with experimental data. The variations in signs and magnitudes of the E2/M1 mixing ratios from nucleus to nucleus for the same class transitions and within a given nucleus for transitions from different spin states suggest that a microscopic approach is needed to explain the data theoretically. The pairing-plus quadrupole model has achieved the first successes in predicting these variations, primarily in the osmium to platinum region.

J. Lange

Papers

E0-E2-M1 multipole admixtures of transitions in even-even nuclei

Erratum: E0-E2-M1 multipole admixtures of transitions in even-even nuclei