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In nuclear physics, the valley of stability (also called the belt of stability, nuclear valley, energy valley, or beta stability valley) is a characterization of the stability of nuclides to radioactivity based on their binding energy.[1] Nuclides are composed of protons and neutrons. The shape of the valley refers to the profile of binding energy as a function of the numbers of neutrons and protons, with the lowest part of the valley corresponding to the region of most stable nuclei.[2] The line of stable nuclides down the center of the valley of stability is known as the line of beta stability. The sides of the valley correspond to increasing instability to beta decay (β− or β+). The decay of a nuclide becomes more energetically favorable the further it is from the line of beta stability. The boundaries of the valley correspond to the nuclear drip lines, where nuclides become so unstable they emit single protons or single neutrons. Regions of instability within the valley at high atomic number also include radioactive decay by alpha radiation or spontaneous fission. The shape of the valley is roughly an elongated paraboloid corresponding to the nuclide binding energies as a function of neutron and atomic numbers.[1]
The nuclides within the valley of stability encompass the entire table of nuclides. The chart of those nuclides is also known as a Segrè chart, after the physicist Emilio Segrè.[3] The Segrè chart may be considered a map of the nuclear valley. The region of proton and neutron combinations outside of the valley of stability is referred to as the sea of instability.[4][5]
Scientists have long searched for long-lived heavy isotopes outside of the valley of stability,[6][7][8] hypothesized by Glenn T. Seaborg in the late 1960s.[9][10] These relatively stable nuclides are expected to have particular configurations of "magic" atomic and neutron numbers, and form a so-called island of stability.
- ^ a b Mackintosh, R.; Ai-Khalili, J.; Jonson, B.; Pena, T. (2001). Nucleus: A trip into the heart of matter. Baltimore, Maryland: The Johns Hopkins University Press. pp. Chapter 6. ISBN 0-801 8-6860-2.
- ^ The valley of stability, 20 June 2013, retrieved 2023-12-01
- ^ Byrne, J. (2011). Neutrons, Nuclei and Matter: An Exploration of the Physics of Slow Neutrons. Mineola, New York: Dover Publications. ISBN 978-0486482385.
- ^ Shaughnessy, D. "Discovery of Elements 113 and 115". Lawrence Livermore National Laboratory. Retrieved July 31, 2016.
- ^ Seaborg, G. T.; Loveland, W.; Morrissey, D. J. (1979). "Superheavy elements: a crossroads". Science. 203 (4382): 711–717. Bibcode:1979Sci...203..711S. doi:10.1126/science.203.4382.711. PMID 17832968. S2CID 20055062.
- ^ Chowdhury, P. Roy; Samanta, C.; Basu, D. N. (2008). "Search for long lived heaviest nuclei beyond the valley of stability". Physical Review C. 77 (4): 044603. arXiv:0802.3837. Bibcode:2008PhRvC..77d4603C. doi:10.1103/PhysRevC.77.044603. S2CID 119207807.
- ^ Rare Isotope Science Assessment; Committee Board on Physics and Astronomy; Division on Engineering and Physical Sciences; National Research Council (2007). Scientific Opportunities with a Rare-Isotope Facility in the United States. National Academies Press. ISBN 9780309104081.
- ^ Boutin, C. (2002). "Climbing out of the nuclear valley". CERN Courier. Retrieved 13 July 2016.
- ^ Seaborg, G. T. (1987). "Superheavy elements". Contemporary Physics. 28: 33–48. Bibcode:1987ConPh..28...33S. doi:10.1080/00107518708211038.
- ^ Sacks (2004). "Greetings From the Island of Stability". The New York Times. Archived from the original on 2023-10-13.