Magic and doubly magic nuclei (and the A = 129, 131, 133 chains). Chapter 4

Nuclear spectroscopy of medium-weight neutron-rich nuclei allows the study of many magic and a few doubly magic isotopes. The most prominent magic numbers intersecting this nuclear region are Z = 50 and N = 50, 82. The crossing of the Z = 50 isotopic chain with the N = 82 isotonic chain results in the doubly magic 132Sn. The study of these nuclei contributes very valuable experimental information for the shell theory. The present knowledge of 132Sn and its neighbours proves the detailed validity of the shell model also far from stability. Several subshells influence the structure of the fission products around A = 100. Here doubly (sub-) magic (94Sr, 96Zr) and deformed nuclei are immediate neighbours. The investigation of excited O+ states is essential for the understanding of the structure in this region as well as in the Ge, Se region. At low masses the nuclei 2868Ni40 and 2878Ni50 are expected to have properties of doubly magic nuclei. The information on the most neutron-rich isobars in the A = 129, 131, 133 chains is reviewed. (author)