Island of stability

A diagram showing the measured and predicted half-lives of heavy and superheavy nuclides, as well as the beta stability line and predicted location of the island of stability.
A diagram by the Joint Institute for Nuclear Research showing the measured (boxed) and predicted half-lives of superheavy nuclides, ordered by number of protons and neutrons. The expected location of the island of stability around Z = 112 (copernicium) is circled.[1][2]

In nuclear physics, the island of stability is a predicted set of isotopes of superheavy elements that may have considerably longer half-lives than known isotopes of these elements. It is predicted to appear as an "island" in the chart of nuclides, separated from known stable and long-lived primordial radionuclides. Its theoretical existence is attributed to stabilizing effects of predicted "magic numbers" of protons and neutrons in the superheavy mass region.[3][4]

Several predictions have been made regarding the exact location of the island of stability, though it is generally thought to center near copernicium and flerovium isotopes in the vicinity of the predicted closed neutron shell at N = 184.[2] These models strongly suggest that the closed shell will confer further stability towards fission and alpha decay. While these effects are expected to be greatest near atomic number Z = 114 (flerovium) and N = 184, the region of increased stability is expected to encompass several neighboring elements, and there may also be additional islands of stability around heavier nuclei that are doubly magic (having magic numbers of both protons and neutrons). Estimates of the stability of the nuclides within the island are usually around a half-life of minutes or days; some optimists propose half-lives on the order of millions of years.[5]

Although the nuclear shell model predicting magic numbers has existed since the 1940s, the existence of long-lived superheavy nuclides has not been definitively demonstrated. Like the rest of the superheavy elements, the nuclides within the island of stability have never been found in nature; thus, they must be created artificially in a nuclear reaction to be studied. Scientists have not found a way to carry out such a reaction, for it is likely that new types of reactions will be needed to populate nuclei near the center of the island. Nevertheless, the successful synthesis of superheavy elements up to Z = 118 (oganesson) with up to 177 neutrons demonstrates a slight stabilizing effect around elements 110 to 114 that may continue in heavier isotopes, consistent with the existence of the island of stability.[2][6]

  1. ^ Zagrebaev, V. (2012). Opportunities for synthesis of new superheavy nuclei (What really can be done within the next few years). 11th International Conference on Nucleus-Nucleus Collisions (NN2012). San Antonio, Texas, US. pp. 24–28. Archived from the original on 3 March 2016.
  2. ^ a b c Karpov, A. V.; Zagrebaev, V. I.; Palenzuela, Y. M.; et al. (2012). "Decay properties and stability of the heaviest elements" (PDF). International Journal of Modern Physics E. 21 (2): 1250013-1–1250013-20. Bibcode:2012IJMPE..2150013K. doi:10.1142/S0218301312500139.
  3. ^ Moskowitz, C. (2014). "Superheavy Element 117 Points to Fabled 'Island of Stability' on Periodic Table". Scientific American. Retrieved 20 April 2019.
  4. ^ Roberts, S. (2019). "Is It Time to Upend the Periodic Table?". The New York Times. Retrieved 27 August 2019.
  5. ^ Cite error: The named reference nuclei was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference beachhead was invoked but never defined (see the help page).

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