Wikipedia:Reference desk/Archives/Science/2024 January 2

= January 2 =

proton numbers and neutron numbers from unstable to stable
We assume:


 * All currently unknown nuclides are more unstable (i.e. have shorter half-life) then all currently known nuclides.

And theoretically, the proton numbers having stable nuclides are 0~66 except 43, 61, 62, 63, and the neutron numbers having stable nuclides are 0~98 except 19, 21, 35, 39, 45, 61, 71, 83~91, 95, 96. We do not consider these two unconfirmed kinds of nuclear decay:


 * proton decay (may be possible, if so, then there are no theoretically stable nuclides)
 * spontaneous fission for the nuclears with mass number < 232 (may be possible for the nuclear with mass number >= 93, if so, then the proton numbers having theoretically stable nuclides are 0~40, and the neutron numbers having theoretically stable nuclides are 0~52 except 19, 21, 35, 39, 45)

For consistency, we regard (proton number, neutron number) = (0, 0) as a theoretically stable nuclide, thus the proton number 0 also has only one stable nuclide, just like the proton numbers 4, 9, 11, 13, 15, 21, 23, … and the neutron numbers 2, 3, 4, 9, 11, 13, 15, …, and the neutron number 0 has two stable nuclides (corresponding to the proton numbers 0 and 1), and every mass number 0~164 except 5, 8, 143~155, 160~162 has exactly one theoretically stable nuclide (which is the only one nuclide with these mass numbers which are stable to both beta decay and double beta decay, see Beta-decay stable isobars).

By the Mattauch isobar rule, all nuclides with proton number 43, 61, … are unstable to beta decay, and all nuclides with neutron numbers 19, 21, 35, 39, 45, 61, 71, 89, 115, 123, 147, … are unstable to beta decay, see Beta-decay stable isobars.

For other proton numbers <= 118 and other neutron numbers <= 178 (which are the proton numbers and the neutron numbers having currently known nuclides) from unstable to stable: (use the data in the "isotopes of elements" articles in Wikipedia, for observationally stable but theoretically unstable (alpha decay, beta decay, double beta decay, electron capture, double electron capture, or isomeric transition) nuclides (i.e. the proton numbers table from "75" and so on, and the neutron numbers table from "111" and so on, respectively), we use the data in )

Proton numbers: (listed up to 98) (not include the proton numbers with theoretically stable nuclides)

Neutron numbers: (listed up to 128) (not include the neutron numbers with theoretically stable nuclides)

Are my two tables right? Also fill these two tables to proton numbers up to 118 and neutron numbers up to 178, respectively. —— 61.223.151.50 (talk) 06:08, 2 January 2024 (UTC)


 * Are you asking people to check that you have correctly looked up numbers and put them in a table, and then look up more numbers and put them in a table for you? It's unclear what your question is. PianoDan (talk) 20:28, 2 January 2024 (UTC)
 * I just mean: The proton numbers 0~98 from unstable to stable are 87, 85, 86, 61, 89, 84, 98, 97, 88, 95, 91, 93, 43, 96, 94, 92, 90, 83, (from here in theory) 75, 71, 74, 73, 72, 69, 76, 77, 79, 70, 78, 68, 63, 82, 62, 67, 81, 80, (0~42 and 44~60 and 64~66, which theoretically have stable nuclides), but what is the proton numbers 0~118 from unstable to stable? Also, the neutron numbers 0~128 from unstable to stable are 39, 128, 115, 89, 35, 19, 45, 127, 61, 123, 21, (from here in theory) 111, 87, 71, 105, 85, 106, 112, 84 (I do not know the theoretically place of 84, since I cannot find the theoretically half-life of the double-beta decay of Ce142), 88, 107, 113, 86, 101, 110, 109, 102, 108, 114, 117, 103, 116, 104, 99, 83, 118, 119, 100, 120, 95, 126, 125, 90, 121, 124, 122, 91, 96, (0~18 and 20 and 22~34 and 36~38 and 40~44 and 46~60 and 62~70 and 72~82 and 92~94 and 97~98, which theoretically have stable nuclides), but what is the proton numbers 0~178 from unstable to stable? 118.170.28.204 (talk) 06:39, 3 January 2024 (UTC)
 * You're esssentially asking us to theoretically extrapolate the lifetimes of many heavy neutron-rich nuclides. I doubt the results at the level of precision you'll need to determine the stability order will be that meaningful right now, since we don't have many experimental results to refine our models in this region. Double sharp (talk) 07:25, 3 January 2024 (UTC)
 * OK, if we only consider the proton numbers or the neutron numbers with no observationally stable nuclides, what is the answer (for these numbers from unstable to stable)? The answer for proton numbers <= 118 is in List of elements by stability of isotopes, but what is the answer for the neutron numbers <= 178? 211.20.197.240 (talk) 07:31, 3 January 2024 (UTC)
 * As that article says (footnote f): "For elements with a higher atomic number than californium (with Z>98), there might exist undiscovered isotopes that are more stable than the known ones." The same problem will affect the higher neutron numbers. If you're happy with predictions (and the fact that these predictions may not actually be correct), then the online JAEA chart of the nuclides might interest you. Double sharp (talk) 08:44, 3 January 2024 (UTC)
 * Well, List of elements by stability of isotopes has the proton numbers <= 118 (with no observationally stable nuclides) from stable to unstable, I just want the neutron numbers <= 178 (with no observationally stable nuclides) from stable to unstable. 211.20.197.240 (talk) 09:17, 3 January 2024 (UTC)
 * You're asking for a lot of work extracting the data from the "isotopes of X" pages (which are organised by Z rather than by N). Not to mention that error bars overlap near the top end (it's not clear whether 292Lv or 293Ts is longer-lived for N = 176, for example). Double sharp (talk) 11:36, 3 January 2024 (UTC)
 * What is the most stable (i.e. longest-lived) nuclide with N neutrons for 129<=N<=134? I just use the Table of nuclides to make my data, but for 129<=N<=134, all nuclides are white, i.e. with half-life < 1 day (this also holds for N>=160, but all 135<=N<=159 have a nuclide with half-life > 1 day). 61.224.143.214 (talk) 05:13, 4 January 2024 (UTC)
 * Okay, this is actually a reasonably-scaled request. They seem to be 212Bi, 212Pb, 214Bi, 214Pb, 216Bi, 221Fr respectively. :) Double sharp (talk) 17:04, 4 January 2024 (UTC)
 * How about N>=160? 223.141.52.225 (talk) 12:18, 5 January 2024 (UTC)
 * Now you're asking about 19 columns on the table of isotopes, and I think we're back to an unreasonable ask. PianoDan (talk) 21:44, 5 January 2024 (UTC)

Finding a particular academic paper
There is a document - probably an academic paper - that has an attached Excel file listing various academic publications discussing palaeoclimate studies that concern North Africa during the Holocene. I think one of these studies listed is about the Fezzan. Does anyone have a link to this paper? I have searched myself on several databases, so far without success. Jo-Jo Eumerus (talk) 09:14, 2 January 2024 (UTC)
 * Perform your search at scholar.google.com instead of a basic search engine to find research papers. 12.116.29.106 (talk) 12:23, 2 January 2024 (UTC)
 * Nope. Tried that, didn't work. There is just no way to usefully narrow things down so that they can catch a supplementary file. Jo-Jo Eumerus (talk) 17:02, 2 January 2024 (UTC)
 * Cambridge University Press publish "Holocene climatic changes in an archaeological landscape: The case study of Wadi Tanezzuft and its drainage basin (SW Fezzan, Libyan Sahara)" Philvoids (talk) 18:55, 2 January 2024 (UTC)
 * Closer, but sans an excel file it's not what I am looking for, I'm afraid. I think it was a ScienceDirect imprint. Jo-Jo Eumerus (talk) 08:19, 3 January 2024 (UTC)


 * This might be teaching grandmother to suck eggs, but I would then use Google Scholar to examine what articles cite that paper, and if any sound relevant I would then examine what articles cite those, etc. For instance, it seems also worth examining who cites "Reconstructing palaeoclimate and hydrological fluctuations in the Fezzan Basin (southern Libya) since 130 ka: A catchment-based approach". If any of the titles that come up in such searches ring any bells with you, you can investigate further whether they have an Excel table as supplementary data; failing that, check all of them. JMCHutchinson (talk) 10:11, 3 January 2024 (UTC)
 * Thanks for the suggestion. It doesn't seem like the paper I am looking for cites these articles, though. I suspect that the Fezzan studies listed were from before 2000. Jo-Jo Eumerus (talk) 13:18, 3 January 2024 (UTC)
 * These articles cite some pre-2000 studies about Fezzan climate (e.g. "Late Quaternary geological evidence for environmental changes in south-western Fezzan (Libyan Sahara)", published 1998), so all I can suggest is that you repeat the "who-cites" operation with some of these. JMCHutchinson (talk) 14:15, 3 January 2024 (UTC)