Unravelling the atomic and nuclear structure of the heaviest elements

February 22, 2017, KU Leuven
The metallic chemical elements known as actinides take their name from the first element in the series: actinium. Actinium is one of the heavy, radioactive elements in Mendeleev’s table that are still largely beyond the frontiers of knowledge. Credit: Shutterstock

Little is known about the heaviest, radioactive elements in Mendeleev's table. But an extremely sensitive technique involving laser light and gas jets makes it possible for the very first time to gain insight into their atomic and nuclear structure. An international team led by scientists from the Institute for Nuclear and Radiation Physics at KU Leuven report these findings in Nature Communications.

In 2016 scientists added four more to Mendeleev's periodic table. These heavy elements are not found on Earth and can only be generated using powerful particle accelerators. "The elements are usually generated in minuscule quantities, sometimes just a couple of atoms per year. These atoms are also radioactive, so their decay is quick: sometimes they only exist for a fraction of a second. That is why scientific knowledge of these elements is very limited," say nuclear physicists Mark Huyse and Piet Van Duppen from the KU Leuven Institute for Nuclear and Radiation Physics.

The KU Leuven researchers are now hoping to change that through a new use of the laser ionization technique. "We produced actinium (Ac), the name-giving element of the heavy actinides, in a series of experiments using the particle accelerator at Louvain-la-Neuve. The quickly decaying atoms of this element were captured in a gas chamber filled with argon, sucked into a supersonic jet, and spotlighted with laser beams. By doing so we bring the outer electron in a different orbit. A second laser beam then shoots the electron away. This ionizes the atom, meaning that it becomes positively charged and is now easy to manipulate and detect. The colour of the is like a fingerprint of the atomic structure of the element and the structure of its nucleus."

In itself, laser ionization is a well-known technique but its use in a is new and very suitable for the heavy, : "By ionizing the atom we significantly increase the sensitivity of the technique. The production of a few atoms per second is already enough for measurements during the experiments. This technology increases the sensitivity, accuracy, and speed of the laser ionization by at least ten times. This marks an entirely new era for research on the heaviest elements and makes it possible to test and correct the theoretical models in nuclear physics. Our method will be used in the new particle accelerator of GANIL, which is currently under construction in France."

Explore further: First spectroscopic investigation of element nobelium

More information: R. Ferrer et al. Towards high-resolution laser ionization spectroscopy of the heaviest elements in supersonic gas jet expansion, Nature Communications (2017). DOI: 10.1038/NCOMMS14520

Related Stories

First spectroscopic investigation of element nobelium

September 30, 2016

The analysis of atomic spectra is of fundamental importance for our understanding of atomic structures. Until now, researchers were unable to examine heavy elements with optical spectroscopy because these elements do not ...

Recommended for you

Researchers study interactions in molecules using AI

October 19, 2018

Researchers from the University of Luxembourg, Technische Universität Berlin, and the Fritz Haber Institute of the Max Planck Society have combined machine learning and quantum mechanics to predict the dynamics and atomic ...

Pushing the extra cold frontiers of superconducting science

October 18, 2018

Measuring the properties of superconducting materials in magnetic fields at close to absolute zero temperatures is difficult, but necessary to understand their quantum properties. How cold? Lower than 0.05 Kelvin (-272°C).

The big problem of small data: A new approach

October 18, 2018

Big Data is all the rage today, but Small Data matters too! Drawing reliable conclusions from small datasets, like those from clinical trials for rare diseases or in studies of endangered species, remains one of the trickiest ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.