Two lowest-energy odd-parity atomic levels of the radioactive element actinium were observed in a laser-spectroscopy experiment at the Johannes Gutenberg University in Mainz, Germany, resolving a long-standing puzzle of “missing” atomic states predicted by theory.
The properties of these states (exact energies, lifetime, and hyperfine structure) were studied by the experimental team and found to be in agreement with atomic-structure calculations carried out by the theory members of the collaboration (including researchers from Germany, China, USA, and Russia).
The results of the work will help in understanding the complex atomic spectra of actinide atoms and may enable developing efficient laser-cooling and ionization schemes for actinium, with possible applications for high-purity medical-isotope production and future fundamental physics experiments.
The experimental team included the members of the group of Prof. Dr. Klaus Wendt of JGU QUANTUM and our group.
https://arxiv.org/abs/2005.03713
Actinium observed in Dmitry Budker’s house