Scientists Explore Superheavy Elements, Revealing Structural Secrets at the Edge of the Periodic Table

Figure 1: The Radiation Detected Resonance Ionisation Spectroscopy setup, located downstream of the UNILAC accelerator, rotating target wheel and velocity filter, SHIP.

(IN BRIEF) A global research collaboration, including scientists from the University of Liverpool, has provided new insights into superheavy elements by examining the nuclear structure of fermium and nobelium isotopes. Using laser spectroscopy, the team measured nuclear radii and discovered that shell effects diminish as elements become heavier, with their nuclei behaving more like a deformed liquid drop. This study offers valuable clues about the possible endpoint of the periodic table and showcases Liverpool’s expertise in laser spectroscopy for rare isotopes. Experiments were conducted at GSI/FAIR and Johannes Gutenberg University Mainz.

(PRESS RELEASE) LIVERPOOL, 11-Nov-2024 — /EuropaWire/ — An international research team, including scientists from the University of Liverpool, has revealed new insights into the atomic structure of superheavy elements, bringing science closer to understanding the limits of the periodic table. The study, published in Nature, investigates the nuclei of fermium (element 100) and nobelium (element 102), specifically examining their structure at extreme neutron and proton counts.

As these elements do not occur naturally, they were synthesized through high-energy nuclear reactions to allow detailed study. By applying advanced laser spectroscopy, the team measured the nuclear radii of various isotopes, finding a notably smooth trend in nuclear structure across neutron numbers, contrasting with the distinct changes seen in lighter elements. This smooth trend suggests that as elements grow heavier, their nuclear shells behave more like a deformed liquid drop, with reduced shell effects as they approach superheavy status.

The University of Liverpool’s Professor Bradley Cheal and Dr. Charlie Devlin contributed to the nobelium experiments by operating specialized laser equipment to probe and measure the atomic hyperfine structure of nobelium atoms. A pivotal isotope was obtained by capturing lawrencium atoms, which were heated, resonantly ionized, and then identified by their alpha decay signature.

Professor Cheal, co-spokesperson for the nobelium experiments, explained, “Our research addresses fundamental questions in nuclear physics regarding neutron and proton extremes and the potential end of the periodic table. This study showcases Liverpool’s expertise in laser spectroscopy, especially in working with rare and radioactive isotopes, at facilities capable of producing these ultra-heavy elements.”

The collaboration, which involved 27 institutes across seven countries, conducted the experiments at Germany’s GSI/FAIR accelerator and Johannes Gutenberg University Mainz. This research expands upon foundational work led by Professor Cheal and published in Nature in 2016, which marked the first use of laser spectroscopy on nobelium.

The full findings of this research, titled “Smooth trends in fermium charge radii and the impact of shell effects” (doi:10.1038/s41586-024-08062-z), are available in Nature.

Media contact:

Sarah Stamper
Media Relations Manager – Science and Engineering
T: +44 (0)7970 247396
E: sarah.stamper@liverpool.ac.uk

SOURCE: University of Liverpool