Michael Block (Germany): Approaching the Island of the Heavyweights

Presently, the Periodic Table comprises 118 elements. The heaviest ones owe their existence to nuclear shell effects providing additional stability against spontaneous fission. Theoretical models even predict an island of stability of long-lived superheavy elements for Z ≈ 114 and N ≈ 184. Such elements feature atomic and nuclear properties that may differ drastically from lighter ones. Nuclear models predict, for example, a central depression in the proton density distribution of such nuclei. Atomic and chemical properties may change due to the strong influence of relativistic and quantum electrodynamic effects. However, small production rates and often short half-lifes make the experimental investigation challenging. Nonetheless, pioneering experiments at the GSI Darmstadt, Germany, have demonstrated that even Penning trap mass spectrometry and laser spectroscopy of the heaviest elements are
feasible. This allowed mapping nuclear shell effects and investigating the nuclear size and shape for Z ≈ 102 and N ≈ 152. I will summarize the status of these activities and discuss some recent results.