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A367461
Number of beta-stable nuclides with neutron excess n, i.e., (neutron number) - (proton number) = n.
7
0, 0, 0, 0, 0, 0, 0, 2, 14, 17, 11, 5, 8, 8, 9, 3, 8, 5, 10, 9, 10, 5, 8, 4, 7, 1, 6, 2, 7, 4, 9, 6, 9, 5, 9, 2, 7, 3, 7, 5, 7, 3, 6, 5, 6, 2, 4, 4, 5, 2, 6, 4, 6, 5, 5, 3, 6, 3, 5, 4, 6, 4, 6, 3
OFFSET
-8,8
COMMENTS
n = -8 represents the most proton-rich nuclide known (nickel-48). A beta-stable nuclide is a nuclide whose beta decay (beta-minus and beta-plus decay) is energetically disallowed; that is to say, a nuclide that has lower energy than its isobars with one more or one less proton. Note that double beta decay is allowed. A nuclide whose beta decay is energetially allowed, even if not observed (in the case of 48Ca, 96Zr, 123Te, 148Gd, 180mTa, 222Rn and 247Cm), is not classified as being beta-stable.
We know of 5 beta-stable nuclides with neutron excess 56 (244Pu, 248Cm, 252Cf, 256Fm, 260No), and it is almost sure that a(56) = 6 with the sixth beta-stable nuclide being the unobserved 264Rf.
Different from A318999: for Z <= 83, 5He, 8Be, 146Sm, 150Gd and 154Dy are beta-stable but not primordial. 40K, 48Ca, 50V, 96Zr, 113Cd, 115In, 123Te, 138La, 176Lu, 187Re and 180mTa are primordial but not beta-stable.
Prediction of a(56)-a(65) from a Russian source: 6, 3, 5, 3, 6, (2, 6, 6 or 3, 6, 5), 6, 3.
Prediction of a(56)-a(85) from pages 14-15 of the Hiroyuki Koura link: 6, 2, 6, 2, 6, 3, 7, 3, 7, 3, 7, 3, 8, 4, 8, 4, 6, 2, 5, 2, 5, 1, 5, 3, 6, 3, 6, 3, 7, 3.
LINKS
Hiroyuki Koura, Decay Modes and a limit of existence of nuclei, 4th International Conference on the Chemistry and Physics of the Transactinide Elements. (See here for an excerpted table.)
Wikipedia, Isodiapher.
EXAMPLE
a(17) = 1 because the only beta-stable nuclide with neutron excess 17 is 117Sn (Z=50, N=67). Note that neither 113Cd nor 115In is beta-stable.
a(22) = 9, with the last three being non-primordial.
a(23) = 6 because there are 6 beta-stable nuclides with neutron excess 23: 131Xe, 133Cs, 135Ba, 141Pr, 143Nd and 147Pm.
a(24) = 9.
a(25) = 5 because there are 5 beta-stable nuclides with neutron excess 25: 137Ba, 139La, 145Nd, 149Sm and 151Eu.
a(45) = 5 because there are 5 beta-stable nuclides with neutron excess 45: 213Po, 215At, 217Rn, 219Fr and 221Ra.
a(47) = 3 because there are 3 beta-stable nuclides with neutron excess 47: 223Ra, 225Ac and 227Th.
CROSSREFS
Cf. A368859 (beta-stable isotopes), A368860 (isotones), A318999.
Sequence in context: A194379 A147832 A022369 * A278975 A096508 A374584
KEYWORD
nonn,hard,fini
AUTHOR
Jianing Song, Jan 26 2024
STATUS
approved