Alpha nuclide
{{Short description|Nuclide made up of alpha particles}}
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.{{cite book |editor=Appenzeller |editor2=Harwit |editor3=Kippenhahn |editor4= Strittmatter |editor5=Trimble |title=Astrophysics Library |publisher=Springer |location=New York |date=1998 |edition=3rd }}{{cite book |last=Carroll |first=Bradley W. |last2=Ostlie |first2=Dale A. |name-list-style= amp |title=An Introduction to Modern Stellar Astrophysics |publisher= Addison Wesley, San Francisco |date=2007 |isbn=978-0-8053-0348-3 }} 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.{{cite book|author=John Avison|title=The World of Physics|url=https://books.google.com/books?id=DojwZzKAvN8C&pg=PA397|date=November 2014|publisher=Nelson Thornes|isbn=978-0-17-438733-6|pages=397–}}
List of alpha nuclides
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.
| class="wikitable" style="margin:auto;"
!width="80"|Alpha number !width="90"|nuclide !width="150"|Stable/radioactive !width="100"|decay mode !width="100"|half-life{{NUBASE2016|ref}} !width="160" |product(s) of decay (bold is stable) !width="100"|alpha decay energy{{AME2020 II|ref}} |
| align="center"| 1
| align="center"| {{nuclide|link=yes|helium|4}} | align="center"| Stable | align="center"| | align="center"| | align="center"| | align="center"| |
| align="center"| 2
| align="center"| {{nuclide|link=yes|beryllium|8}} | align="center"| Radioactive | align="center"| α | align="center"| 8.19(37)×10−17 s | align="center"| {{nuclide|link=yes|helium|4}} | align="center"| +0.09184MeV |
| align="center"| 3
| align="center"| {{nuclide|link=yes|carbon|12}} | align="center"| Stable | align="center"| | align="center"| | align="center"| | align="center"| -7.36659MeV |
| align="center"| 4
| align="center"| {{nuclide|link=yes|oxygen|16}} | align="center"| Stable | align="center"| | align="center"| | align="center"| | align="center"| -7.16192MeV |
| align="center"| 5
| align="center"| {{nuclide|link=yes|neon|20}} | align="center"| Stable | align="center"| | align="center"| | align="center"| | align="center"| -4.72985MeV |
| align="center"| 6
| align="center"| {{nuclide|link=yes|magnesium|24}} | align="center"| Stable | align="center"| | align="center"| | align="center"| | align="center"| -9.31656MeV |
| align="center"| 7
| align="center"| {{nuclide|link=yes|silicon|28}} | align="center"| Stable | align="center"| | align="center"| | align="center"| | align="center"| -9.98414MeV |
| align="center"| 8
| align="center"| {{nuclide|link=yes|sulfur|32}} | align="center"| Stable | align="center"| | align="center"| | align="center"| | align="center"| -6.94766MeV |
| align="center"| 9
| align="center"| {{nuclide|link=yes|argon|36}} | align="center"| Observationally Stable | align="center"| (ECEC) | align="center"| never seen | align="center"| ({{nuclide|link=yes|sulfur|36}}) | align="center"| -6.64092MeV |
| align="center"| 10
| align="center"| {{nuclide|link=yes|calcium|40}} | align="center"| Observationally Stable | align="center"| (ECEC) | align="center"| never seen | align="center"| ({{nuclide|link=yes|argon|40}}) | align="center"| -7.03978MeV |
| align="center"| 11
| align="center"| {{nuclide|link=yes|titanium|44}} | align="center"| Radioactive | align="center"| EC | align="center"| 60.0(11) y | align="center"| {{nuclide|link=yes|scandium|44}} → {{nuclide|link=yes|calcium|44}} | align="center"| -5.1271MeV |
| align="center"| 12
| align="center"| {{nuclide|link=yes|chromium|48}} | align="center"| Radioactive | align="center"| β+ | align="center"| 21.56(3) h | align="center"| {{nuclide|link=yes|vanadium|48}} → {{nuclide|link=yes|titanium|48}} | align="center"| -7.698MeV |
| align="center"| 13
| align="center"| {{nuclide|link=yes|iron|52}} | align="center"| Radioactive | align="center"| β+ | align="center"| 8.275(8) h | align="center"| {{nuclide|link=yes|manganese|52|m}} → {{nuclide|link=yes|chromium|52}} | align="center"| -7.936MeV |
| align="center"| 14
| align="center"| {{nuclide|link=yes|nickel|56}} | align="center"| Radioactive | align="center"| β+ | align="center"| 6.075(10) d | align="center"| {{nuclide|link=yes|cobalt|56}} → {{nuclide|link=yes|iron|56}} | align="center"| -8.0005MeV |
| align="center"| 15
| align="center"| {{nuclide|link=yes|zinc|60}} | align="center"| Radioactive | align="center"| β+ | align="center"| 2.38(5) min | align="center"| {{nuclide|link=yes|copper|60}} → {{nuclide|link=yes|nickel|60}} | align="center"| -2.6917MeV |
| align="center"| 16
| align="center"| {{nuclide|link=yes|germanium|64}} | align="center"| Radioactive | align="center"| β+ | align="center"| 63.7(25) s | align="center"| {{nuclide|link=yes|gallium|64}} → {{nuclide|link=yes|zinc|64}} | align="center"| -2.566MeV |
| align="center"| 17
| align="center"| {{nuclide|link=yes|selenium|68}} | align="center"| Radioactive | align="center"| β+ | align="center"| 35.5(7) s | align="center"| {{nuclide|link=yes|arsenic|68}} → ... → {{nuclide|link=yes|zinc|68}} | align="center"| -2.299MeV |
| align="center"| 18
| align="center"| {{nuclide|link=yes|krypton|72}} | align="center"| Radioactive | align="center"| β+ | align="center"| 17.16(18) s | align="center"| {{nuclide|link=yes|bromine|72}} → ... → {{nuclide|link=yes|germanium|72}} | align="center"| -2.176MeV |
| align="center"| 19
| align="center"| {{nuclide|link=yes|strontium|76}} | align="center"| Radioactive | align="center"| β+ | align="center"| 7.89(7) s | align="center"| {{nuclide|link=yes|rubidium|76}} → ... → {{nuclide|link=yes|selenium|76}} | align="center"| -2.73MeV |
| align="center"| 20
| align="center"| {{nuclide|link=yes|zirconium|80}} | align="center"| Radioactive | align="center"| β+ | align="center"| 4.6(6) s | align="center"| {{nuclide|link=yes|yttrium|80}} → ... → {{nuclide|link=yes|krypton|80}} | align="center"| -3.70MeV |
| align="center"| 21
| align="center"| {{nuclide|link=yes|molybdenum|84}} | align="center"| Radioactive | align="center"| β+ | align="center"| 3.8(9) ms | align="center"| {{nuclide|link=yes|niobium|84}} → ... → {{nuclide|link=yes|strontium|84}} | align="center"| -2.71MeV |
| align="center"| 22
| align="center"| {{nuclide|link=yes|ruthenium|88}} | align="center"| Radioactive | align="center"| β+ | align="center"| 1.3(3) s | align="center"| {{nuclide|link=yes|technetium|88}} → ... → {{nuclide|link=yes|strontium|88}} | align="center"| -2.27MeV |
| align="center"| 23
| align="center"| {{nuclide|link=yes|palladium|92}} | align="center"| Radioactive | align="center"| β+ | align="center"| 1.1(3) s | align="center"| {{nuclide|link=yes|rhodium|92}} → ... → {{nuclide|link=yes|molybdenum|92}} | align="center"| -2.28MeV |
| align="center"| 24
| align="center"| {{nuclide|link=yes|cadmium|96}} | align="center"| Radioactive | align="center"| β+ | align="center"| 1.003(47) s | align="center"| {{nuclide|link=yes|silver|96}} → ... → {{nuclide|link=yes|ruthenium|96}} | align="center"| -3.03MeV |
| align="center"| 25
| align="center"| {{nuclide|link=yes|tin|100}} | align="center"| Radioactive | align="center"| β+ | align="center"| 1.1(4) s | align="center"| {{nuclide|link=yes|indium|100}} → ... → {{nuclide|link=yes|ruthenium|100}} | align="center"| -3.47MeV |
| align="center"| 26
| align="center"| {{nuclide|link=yes|tellurium|104}} | align="center"| Radioactive | align="center"| α | align="center"| <18 ns | align="center"| {{nuclide|link=yes|tin|100}} → ... → {{nuclide|link=yes|ruthenium|100}} | align="center"| +5.10MeV |
| align="center"| 27
| align="center"| {{nuclide|link=yes|xenon|108}} | align="center"| Radioactive | align="center"| α | align="center"| 58{{su|p=+106|b=−23}} μs | align="center"| {{nuclide|link=yes|tellurium|104}} → {{nuclide|link=yes|tin|100}} → ... → {{nuclide|link=yes|ruthenium|100}} | align="center"| +4.57MeV |
{{as of|2024}}, the heaviest known alpha nuclide is xenon-108.{{cite journal |last=Auranen |first=K. |display-authors=etal |date=2018 |title=Superallowed α decay to doubly magic 100Sn |journal=Physical Review Letters |volume=121 |issue=18 |pages=182501 |doi=10.1103/PhysRevLett.121.182501 |pmid=30444390 |url=https://www.pure.ed.ac.uk/ws/files/77942573/PhysRevLett.121.pdf |doi-access=free }}
References
{{reflist}}