One of the most important factors for understanding the atomic structure of any element is its atomic spectrum analysis. Till date, researchers weren’t able to put any heavy element to examination via optical spectroscopy. Reason being, these elements have no natural occurrence and it is not possible to create these in any weighable quantity. Nevertheless, a team of researchers was recently successful in taking a look into the inner structure of a heavy element. For this purpose, they mainly used the short-lived nobelium atoms that have a nuclear charge of Z=102, this one was created at a GSO accelerator facility.
The team was able to examine a single atom of this element with the help of laser spectroscopy. This experiment was carried under an international collaboration under the leadership of Superheavy Elements Physics at the GSI Helmholtzzentrum für Schwerionenforschung. The team had scientists coming from several institutes including the University of Liverpool, the Katholieke Universiteit Leuven, the GSI Helmholtzzentrum für Schwerionenforschung, the Technische Universität Darmstadt, and several others.
The periodic table has witnessed the discovery of 118 elements till date, however, scientists were unable to probe any element ahead of fermium that carries more than one hundred protons in its nucleus. The number of electrons is same in the surrounding shells. The main challenge in the further investigation was probed by the high speed of electrons that cause relativistic effects over orbit atomic nuclei with some very high proton numbers along with interactions between multiple electrons. Nobelium was no easy target with respect to exploration. The method adopted by the team was an extremely sensitive one that was developed by all the researchers together.
As professor Michael Block, the head of the department of Superheavy Elements Physics at GSI quotes, “At the GSI accelerator facility, we bombarded thin films of the lead with calcium projectiles in order to create the isotope nobelium-254 by fusing the atomic nuclei of the reaction partners. We then used the SHIP separator to isolate the nobelium isotopes, which enabled us to irradiate them with laser light.” \
If correct transition energy is sent, the laser light gets absorbed and the electron is removed from the outer shell of an atom and converted into a positive ion. This ion is then identified through its radioactive decay, Dr. Mustapha Laatiaoui, the lead scientist from GSI adds, “The experiment unit is so sensitive that only about four atoms need to be created per second for our experiments. The radioactive nobelium atoms exist for only 50 seconds before they decay again.