Protons do not like to stay close to each other for very long. But if you have the right number perfectly balanced between enough neutrons, they could build an atom that won’t collapse in an instant.
Theorists have suggested that 114 may be such a “magic” number of protons – but a recent experiment at the GSI Helmholtz Center for Heavy Ion Research in Germany now makes this incredibly unlikely.
In 1998, Russian experimenters finally managed to build an element with 114 protons in its nucleus. It was later named flerovium after its birthplace, the Flerov Nuclear Reaction Laboratory of the Joint Institute for Nuclear Research.
Creating atoms the size of a mammoth is not at all easy, done only by starting with heavy elements such as plutonium and throwing them away with slightly smaller ones, such as calcium, until something sticks.
By “sticks” we mean “breaks long enough to pass technically after an atom”, which for mountain-sized nuclei is rarely more than a fraction of a second. For example, at 112 protons in size, the transuranic element of Copernicus has little chance of lasting more than 280 microseconds.
Atomic nucleons hold each other as an effect of the strong force divided between the tri-atomic quark trios that make them up.
At the same time, the repulsive nature of the positive charges in the protons pushes them, which means that the whole structure shakes on the verge of collapse, if they get too close. This is why we see some combinations of nucleons, or isotopes, more often than others.
Once an atom reaches a certain size, a lot of other factors related to energy and mass are weighed, making it increasingly difficult for the atom to hold together, not to mention more difficult for physicists to and predicts the characteristics.
However, physicists are confident that there are islands of stability at the top of the periodic table, where proton arrangements can form patterns and shapes that allow them to last a little longer than neighboring elements.
Nihonium, or element 113, has an isotope with a half-life of about 20 seconds, for example.
However, when the signs of flerovium were first screened from a remnant of plutonium and calcium more than 20 years ago, however, it looked like a true holder. The signature from the data suggested that the atoms remained stable for up to 30 seconds before spitting out an alpha particle and briefly collapsing into the copernicium.
The emotion was short-lived. In 2009, Berkeley scientists were able to recreate two different isotopes of the element. One lasted a tenth of a second. The second one remained around for a longer touch, falling after half a second.
Chances didn’t look good for element 114, but physicists aren’t the kind to leave them alone well enough. So the University of Mainz became big, using updated detectors to study dozens of possible events of disintegration of the flower.
Finally, two were confirmed as isotopes of good faith. One resulted in a copernicium isotope that was seen to decompose in a way that had not been observed before.
In this case, the disintegration chain of the fleece occurred in 2.4 seconds in an alpha particle spill. The second isotope disappeared in 52.6 milliseconds. Importantly, the efficient way in which each of the two isotopes decomposed clearly showed that 114 was not at least stable.
As interesting as a stable flerovium may have been, new discoveries of an excited state of copernicium provide solid ground for exploring the islands of stability above in the periodic table, providing theorists with vital information for further modeling this phenomenon.
“The existence of the state provides yet another anchor for nuclear theory, as it seems to require an understanding of both the coexistence of form and the transitions of form for the heaviest elements,” the researchers note in their report.
Although we can now exclude only 114 as one of the magic numbers in the periodic table, there are giants left to kill.
Physicists have not yet created the hypothetical element provisionally called unbinilium or element 120. The creation of one of these monsters would require strong technology and advanced knowledge of nuclear physics.
There are plans in place to push the boundaries of atomic masses, with RIKEN in Japan making steady progress at its Accelerator-Based Science Center in Nishina, so we may not have to wait long.
Like ancient explorers, researchers are still confident that there are stable islands right on the horizon. We need to see some mirages along the way.
This research was published in Physical review letters.