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Alpha nuclide

From Wikipedia, the free encyclopedia

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

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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
2
He
Stable
2 8
4
Be
Radioactive α 8.19(37)×10−17 s 4
2
He
+0.09184MeV
3 12
6
C
Stable -7.36659MeV
4 16
8
O
Stable -7.16192MeV
5 20
10
Ne
Stable -4.72985MeV
6 24
12
Mg
Stable -9.31656MeV
7 28
14
Si
Stable -9.98414MeV
8 32
16
S
Stable -6.94766MeV
9 36
18
Ar
Observationally Stable (ECEC) never seen (36
16
S
)
-6.64092MeV
10 40
20
Ca
Observationally Stable (ECEC) never seen (40
18
Ar
)
-7.03978MeV
11 44
22
Ti
Radioactive EC 60.0(11) y 44
21
Sc
 → 44
20
Ca
-5.1271MeV
12 48
24
Cr
Radioactive β+ 21.56(3) h 48
23
V
 → 48
22
Ti
-7.698MeV
13 52
26
Fe
Radioactive β+ 8.275(8) h 52m
25
Mn
 → 52
24
Cr
-7.936MeV
14 56
28
Ni
Radioactive β+ 6.075(10) d 56
27
Co
 → 56
26
Fe
-8.0005MeV
15 60
30
Zn
Radioactive β+ 2.38(5) min 60
29
Cu
 → 60
28
Ni
-2.6917MeV
16 64
32
Ge
Radioactive β+ 63.7(25) s 64
31
Ga
 → 64
30
Zn
-2.566MeV
17 68
34
Se
Radioactive β+ 35.5(7) s 68
33
As
 → ... → 68
30
Zn
-2.299MeV
18 72
36
Kr
Radioactive β+ 17.16(18) s 72
35
Br
 → ... → 72
32
Ge
-2.176MeV
19 76
38
Sr
Radioactive β+ 7.89(7) s 76
37
Rb
 → ... → 76
34
Se
-2.73MeV
20 80
40
Zr
Radioactive β+ 4.6(6) s 80
39
Y
 → ... → 80
36
Kr
-3.70MeV
21 84
42
Mo
Radioactive β+ 3.8(9) ms 84
41
Nb
 → ... → 84
38
Sr
-2.71MeV
22 88
44
Ru
Radioactive β+ 1.3(3) s 88
43
Tc
 → ... → 88
38
Sr
-2.27MeV
23 92
46
Pd
Radioactive β+ 1.1(3) s 92
45
Rh
 → ... → 92
42
Mo
-2.28MeV
24 96
48
Cd
Radioactive β+ ~1 s 96
47
Ag
 → ... → 96
44
Ru
-3.03MeV
25 100
50
Sn
Radioactive β+ 1.1(4) s 100
49
In
 → ... → 100
44
Ru
-3.47MeV
26 104
52
Te
Radioactive α <18 ns 100
50
Sn
 → ... → 100
44
Ru
+5.10MeV
27 108
54
Xe
Radioactive α 58+106
−23
 μs
104
52
Te
 → 100
50
Sn
 → ... → 100
44
Ru
+4.57MeV

As of 2024, the heaviest known alpha nuclide is xenon-108.[6]

References

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  1. ^ Appenzeller; Harwit; Kippenhahn; Strittmatter; Trimble, eds. (1998). Astrophysics Library (3rd ed.). New York: Springer.
  2. ^ Carroll, Bradley W. & Ostlie, Dale A. (2007). An Introduction to Modern Stellar Astrophysics. Addison Wesley, San Francisco. ISBN 978-0-8053-0348-3.
  3. ^ John Avison (November 2014). The World of Physics. Nelson Thornes. pp. 397–. ISBN 978-0-17-438733-6.
  4. ^ 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.
  5. ^ 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.
  6. ^ 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.