Alpha nuclide
An alpha nuclide is a nuclide that consists of an integer number of alpha particles. Alpha nuclides have equal, even numbers of protons and neutrons; they are important in stellar nucleosynthesis since the energetic environment within stars is amenable to fusion of alpha particles into heavier nuclei.[1][2] Stable alpha nuclides, and stable decay products of radioactive alpha nuclides, are some of the most common metals in the universe.
Alpha nuclide is also shorthand for alpha radionuclide, referring to those radioactive isotopes that undergo alpha decay and thereby emit alpha particles.[3]
List of alpha nuclides
[edit]The entries for 36Ar and 40Ca are theoretical: they would release energy on decay, but the process has never been observed, and the half-lives are probably extremely long. Likewise, the chains for masses 64, 84, 92, and 96 theoretically can continue one more step by double electron capture (to 64Ni, 84Kr, 92Zr, and 96Mo respectively), but this has never been observed.
| Alpha number | nuclide | Stable/radioactive | decay mode | half-life[4] | product(s) of decay (bold is stable) | alpha decay energy[5] |
|---|---|---|---|---|---|---|
| 1 | 4 2He | Stable | ||||
| 2 | 8 4Be | Radioactive | α | 8.19(37)×10−17 s | 4 2He | +0.09184MeV |
| 3 | 12 6C | Stable | -7.36659MeV | |||
| 4 | 16 8O | Stable | -7.16192MeV | |||
| 5 | 20 10Ne | Stable | -4.72985MeV | |||
| 6 | 24 12Mg | Stable | -9.31656MeV | |||
| 7 | 28 14Si | Stable | -9.98414MeV | |||
| 8 | 32 16S | Stable | -6.94766MeV | |||
| 9 | 36 18Ar | Observationally Stable | (ECEC) | never seen | (36 16S ) | -6.64092MeV |
| 10 | 40 20Ca | Observationally Stable | (ECEC) | never seen | (40 18Ar ) | -7.03978MeV |
| 11 | 44 22Ti | Radioactive | EC | 60.0(11) y | 44 21Sc → 44 20Ca | -5.1271MeV |
| 12 | 48 24Cr | Radioactive | β+ | 21.56(3) h | 48 23V → 48 22Ti | -7.698MeV |
| 13 | 52 26Fe | Radioactive | β+ | 8.275(8) h | 52m 25Mn → 52 24Cr | -7.936MeV |
| 14 | 56 28Ni | Radioactive | β+ | 6.075(10) d | 56 27Co → 56 26Fe | -8.0005MeV |
| 15 | 60 30Zn | Radioactive | β+ | 2.38(5) min | 60 29Cu → 60 28Ni | -2.6917MeV |
| 16 | 64 32Ge | Radioactive | β+ | 63.7(25) s | 64 31Ga → 64 30Zn | -2.566MeV |
| 17 | 68 34Se | Radioactive | β+ | 35.5(7) s | 68 33As → ... → 68 30Zn | -2.299MeV |
| 18 | 72 36Kr | Radioactive | β+ | 17.16(18) s | 72 35Br → ... → 72 32Ge | -2.176MeV |
| 19 | 76 38Sr | Radioactive | β+ | 7.89(7) s | 76 37Rb → ... → 76 34Se | -2.73MeV |
| 20 | 80 40Zr | Radioactive | β+ | 4.6(6) s | 80 39Y → ... → 80 36Kr | -3.70MeV |
| 21 | 84 42Mo | Radioactive | β+ | 3.8(9) ms | 84 41Nb → ... → 84 38Sr | -2.71MeV |
| 22 | 88 44Ru | Radioactive | β+ | 1.3(3) s | 88 43Tc → ... → 88 38Sr | -2.27MeV |
| 23 | 92 46Pd | Radioactive | β+ | 1.1(3) s | 92 45Rh → ... → 92 42Mo | -2.28MeV |
| 24 | 96 48Cd | Radioactive | β+ | ~1 s | 96 47Ag → ... → 96 44Ru | -3.03MeV |
| 25 | 100 50Sn | Radioactive | β+ | 1.1(4) s | 100 49In → ... → 100 44Ru | -3.47MeV |
| 26 | 104 52Te | Radioactive | α | <18 ns | 100 50Sn → ... → 100 44Ru | +5.10MeV |
| 27 | 108 54Xe | Radioactive | α | 58+106 −23 μs | 104 52Te → 100 50Sn → ... → 100 44Ru | +4.57MeV |
As of 2024[update], the heaviest known alpha nuclide is xenon-108.[6]
References
[edit]- ^ Appenzeller; Harwit; Kippenhahn; Strittmatter; Trimble, eds. (1998). Astrophysics Library (3rd ed.). New York: Springer.
- ^ Carroll, Bradley W. & Ostlie, Dale A. (2007). An Introduction to Modern Stellar Astrophysics. Addison Wesley, San Francisco. ISBN 978-0-8053-0348-3.
- ^ John Avison (November 2014). The World of Physics. Nelson Thornes. pp. 397–. ISBN 978-0-17-438733-6.
- ^ Audi, G.; Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S. (2017). "The NUBASE2016 evaluation of nuclear properties" (PDF). Chinese Physics C. 41 (3): 030001. Bibcode:2017ChPhC..41c0001A. doi:10.1088/1674-1137/41/3/030001.
- ^ Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references". Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf.
- ^ Auranen, K.; et al. (2018). "Superallowed α decay to doubly magic 100Sn" (PDF). Physical Review Letters. 121 (18): 182501. doi:10.1103/PhysRevLett.121.182501. PMID 30444390.