Talk:Magic number (physics)

message: Table isotopes en.svg
The image needs to be corrected, there are a number of places where there is beta minus decay diagonally opposite beta plus decay.  This is inaccurate as it implies the atoms here would just oscillate between these states emitting (anti)electrons - which isn't possible.  —Preceding unsigned comment added by Billy Huang (talk • contribs) 22:23, 24 June 2010 (UTC)
replies: text: Possible if you keep feeding it with energy. JIMp talk·cont 07:06, 25 January 2011 (UTC)
thread_title:  Image incorrect 

message: I removed 6 and 14, they're not magic numbers, even according to the link provided.
I doubt that 2 is a magic number, because I know for certain that Helium has a far  lower nucleus energy state than Deuterium. (Source: My Physics school book)
:Interesting.  My source is http://www.research.att.com/projects/OEIS?Anum=A018226.  I'll check my physics textbooks to confirm, too.  Giftlite 23:54, 24 Mar 2004 (UTC)
replies: text: Yes, , two protons & two neutrons, is in a very low energy state.  This is because two is magic. JIMp talk·cont 07:02, 25 January 2011 (UTC)
thread_title:  Not Magic 

message: I believe the magic numbers refer to number of protons OR number of neutrons, not the sum. So Helium 4 is especially stable because it has both 2 protons and 2 neutrons.
:A reference - http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/shell.html.  Giftlite 01:12, 8 May 2004 (UTC)
thread_title:  Belief 

message: Friends, I have it on good authority that three is a magic number, yet it is missing from the list.
Should the list be marked incomplete? 86.20.180.82 20:04, 7 May 2007 (UTC)
replies: text: No, 3 is not a magic number. What good authority? I have citable one. Say lecture notes : Nuclear and Particle Physics, University of Edinburgh - Dr Daniel Watts; or book : Introduction to Nuclear and Particle Physics 2nd Edition, A. Das and T. Ferbel. -- KTC 00:01, 15 May 2007 (UTC)

text: Magic numbers have to be even. Because of Fermi-Dirac pairing, each level holds to protons or two neutrons. Such pairing is also why even-even nuclides are more stable, and odd-odd are rare. Also, the extra stability of an even number of neutrons is what allows for slow neutron fission. Gah4 (talk) 05:37, 4 September 2017 (UTC)
thread_title:  What of three? 

message: Dear Wiki editors, over the past months some of you have made reference to the non empirical derivation by Xavier Borg, namely our paper 'Magic numbers derived from variable phase nuclear model' on-line at http://www.blazelabs.com/magicnumbers.pdf
There seems to be some disagreement upon whether or not such work should be cited on Wikipedia, which pretty messed up this talk page as shown in its history, so I'm cleaning this up and clearing the point in question. The above referenced paper IS original research, and is strictly NOT peer-reviewed, even though some university students collaborated with us to generate peer- reviewed scientific papers based on the core of its content. Keep in mind, Wiki, is used mainly by mainstream education, and is used by many scholars, and does not permit original research to be published. So, please, even though the contents of this paper read like common sense to some of you, I hereby ask you to refrain from copying any of its contents on the magic numbers page, since this would go against Wiki's policies, and would also breach copyright laws. If anybody sees the necessity of referencing this work, I would suggest to add it as an external link, and clearly label it as 'non mainstream'. Thanks. 
(Blaze Labs Research (talk) 06:54, 3 July 2008 (UTC)
replies: text: Copyright protects the expression of ideas, not the ideas themselves. All wikipedia editors, and journal authors in general, should know how to express an idea in their own words, and avoid copyright problems.  I don't know of a rule against non-peer reviewed articles, though a single source is not, in general, good enough. Gah4 (talk) 05:42, 4 September 2017 (UTC)
thread_title:  Original Research  

message: I removed 6 and 14, they're not magic numbers, even according to the link provided.
I doubt that 2 is a magic number, because I know for certain that Helium has a far  lower nucleus energy state than Deuterium. (Source: My Physics school book)
:Interesting.  My source is http://www.research.att.com/projects/OEIS?Anum=A018226.  I'll check my physics textbooks to confirm, too.  Giftlite 23:54, 24 Mar 2004 (UTC)
thread_title:  Not Magic 

message: I believe the magic numbers refer to number of protons OR number of neutrons, not the sum. So Helium 4 is especially stable because it has both 2 protons and 2 neutrons.
:A reference - http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/shell.html.  Giftlite 01:12, 8 May 2004 (UTC)
thread_title:  Belief 

message: Sorry if this is a stupid question, but, based on what is in this article, how can Hassium-270 be doubly magic when neither 108 nor 162 are magic numbers? A good answer could be used to improve this article, so the next person doesn't have to ask :) Skittle 16:21, 9 November 2007 (UTC)
replies: text: Why don't you read the ref., which is anpunished (not depublished).  Other magic numera may be ±12-off or ±6-off.  How do you think 114 came up when it's not even in the series? -lysdexia 11:04, 17 March 2008 (UTC)
thread_title:  [[Hassium]] 

message: Fisdof9 proposed to merge article Magic number (chemistry) into this one. Actually, I don't think this is appropriate because the cause for the existence of magic numbers for atomic nuclei and the chemical clusters is quite different. In the first case it is due to the strong and electromagnetic interaction, in the latter case due to chemical forces.
This difference will become more obvious if someone expands the "Magic number (chemistry)" article. The only common thing is that the same concept can be used to understand the existence of magic numbers.
--Cyfal (talk) 09:55, 21 June 2008 (UTC)
replies: text: Well, because there have been no further contributions to this discussion, I remove the merger proposal now. --Cyfal (talk) 15:20, 10 August 2008 (UTC)
replies: text: Both are side effects of Pauli exclusion, but the interactions are different, and so the numbers are different. It seems to me that they deserve separate articles, but maybe not so obvious. Gah4 (talk) 01:01, 12 November 2016 (UTC)
thread_title:  Proposed merger 

message: Today the text includes: "as of 2007, the longest-lived, known isotope among all of the elements between 110 and 120 lasts only 12 min., next 22 sec"
Surely "lasts" should be replaced by "have half lives of", actual isotopes should be given, and citations quoted.
NickSharp (talk) 05:28, 12 October 2008 (UTC)
replies: text: I would remove that sentence, for example Uub-285 has half-life 40±30 min. —Quilbert (talk) 18:21, 26 November 2008 (UTC)
thread_title:  "Lasts"?  Which isotopes?  Citations? 

message: Ni-28 is not the most proton rich isotope, regardless of what the cited source says.
Ni-28 has a 7/5 Proton/Neutron ratio.  
He-3 has a 2/1 Proton/Neutron ratio.
H-1 has a 1/0 Proton/Neutron ratio.
Ni-28 is the most proton rich isotope beyond helium-3  —Preceding unsigned comment added by 70.130.130.193 (talk) 19:03, 7 April 2009 (UTC)
replies: text: Actually Ni-48 can hold together (half-life >500 ns, theorized to be 10 ms), though I suspect this is only because it is doubly magic. Double sharp (talk) 02:14, 20 July 2014 (UTC)
thread_title:  Ni-28 not most proton rich isotope 

message: Is there a generally-accepted definition of what 'magic' means, apart from the vague idea "more stable than the rest" or "with complete shells" (although the shell model is not universally accepted either)? In an article in the current issue (7) of Physik Journal (for members of the German Physics Society/Deutsche Physikalische Gesellschaft), Jan Jolie and Peter Reiter from Darmstadt state that the only criterion for a shell closure (presumably w.r.t magicity) is the energy gap between completed levels. This is backed up with data relating to 30Si and 24O (both with 16 neutrons), whereby 24O is deemed to be magic due to the larger energy gap and 30Si, with a smaller gap, is not. On this basis, 24O is doubly magic (Z=8 and N=16). It certainly seems odd that the term "magic" seems to have mean different things to different people: Everyone 'knows' what it means but there doesn't seems to be a universal definition. --TraceyR (talk) 13:07, 8 July 2009 (UTC)
thread_title:  Definition of 'magic'? 

message: Several people have found connections between the nuclear (semi)magic numbers and the Pascal Triangle's values.
Because of the way spin-orbit coupling splits orbitals and the way the energy levels of these parts interact, there are two different types of (semi)magic number. They can be rationalized in pairs 2 2 : 6 8 : 14 20 : 28 40 : 50 70 : 82 112 : 126 168 : 184 240 and so on. The right member of each pair is a doubled Pascal Triangle tetrahedral number- in fact each in sequence as- 2=2x1, 8=2x4, 20=2x10, 40=2x20, 70=2x35, 112=2x56, 168=2x84, 240=2x120, etc.
The left member of each pair can be represented two ways, either as a doubled tetrahedral value with the doubled triangular value directly above it in the Triangle subtracted from it (for example 112-30=82, 168-42=126, where 30 and 42 are doubled triangular numbers), or as doubled tetrahedral numbers plus an even integer increment that comes from the doubled natural number line, where the particular number falls along the same shallow diagonal as the doubled tetrahedral numbers it adds to, such shallow diagonals also used to sum Fibonacci numbers (here doubled).
There are several more such Pascal-related mathematical behaviors in the nuclear system. Interestingly there are also Pascal mathematical behaviors in the electronic system, though these are based not on doubled, but normal single values. 69.121.117.192 (talk) 23:56, 28 September 2012 (UTC)
thread_title:  Pascal Magic 

message: http://en.wikipedia.org/wiki/Electron_shell   <--  Seems to be the source
"This is equivalent to saying that the outer electron shell is 'full'."
That article has tons of sources for this claim.
75.70.89.124 (talk) 07:02, 31 July 2013 (UTC)
thread_title:  Unsourced? 

message: This article does not make it obvious enough that magic numbers are computed separately for protons and neutrons. Note that the usual pictures that people draw of nuclei have a ball of separate protons and neutrons.  But there is no Pauli exclusion between them, so there is no need for them to be separate. Also, ones of opposite spin don't have exclusion. Gah4 (talk) 00:55, 12 November 2016 (UTC)
thread_title:  Separately 

message: It would be helpful to simply LIST the stable or nearly-stable isotopes with just magic numbers of neutrons.
2, 8, 20, 28, 50, 82, and 126. Easy to do, too, but it's not so easy to make it complete.
These start the list: He-3, N-15, S-38, Cl-37, Ar-38, K-39, all stable.  
Ti-50, V-51 (its only stable isotope), Cr-52, Fe-54. 
Rb-87 with a very long half-life, Sr-88, Y-89 (its only stable isotope), Zr-90, and Mo-92.
These are the elements helium (two stable isotopes), nitrogen (two stable isotopes), sulfur (four stable isotopes), chlorine (just two), argon (just three), potassium (just two), titanium (five stable isotopes), vanadium (just one), chromium (four stable isotopes), iron (four stable isotopes), rubidium (one stable isotope Rb-85), strontium (four stable isotopes), yttrium (just one), zirconium (four stable isotopes), and molybdenum (six stable isotopes, but Mo-92 being the lightest one).
I will let you other weenies figure out the ones with 82 and 126 neutrons. I would have thought that there was a magic number of neutrons associated with thorium-232, uranium-238, and plutonium-242, but this is not so.  
The number 20 + 20 = 40 is an interesting one, but it is not a magic one.
Ca-40, with 20p and 20n, is very, very stable for its atomic mass number.
K-40, with 19p and 21n, decays three ways, into Ar-40 (18p + 22n) or Ca-40 (20p + 20n), by electron capture or positron emission.
Also, the two nearby isotopes, K-39 and K-41, are both stable, but Ca-39 and Ca-41 is radioactive, despite having 20 protons. Ar-39, Ar-41, and Sc-41 are all radioactive. The most common isotope of argon on the Earth is Ar-40, but in the Universe it is Ar-36 (18p + 18n).
47.215.183.159 (talk) 02:02, 4 September 2017 (UTC)
replies: text: I listed the elements to cover the proton magic numbers. Feel free to add a list of isotopes with magic neutron numbers. --mfb (talk) 14:52, 4 September 2017 (UTC)
replies: text: Th and U have semi-closed shells, at least theoretically, though since actinide nuclei are not spherical the applicability of the unaltered shell model is a little suspect. Double sharp (talk) 15:06, 3 December 2017 (UTC)
thread_title:  Chemical elements with magic numbers of neutrons. 

message: Recently more nuclides were added to a paragraph on double magic nuclides. I believe that is fine, but also that we should separate stable (or almost stable) from unstable ones. Ca-40 and Ca-48 have a 1e28s or so half life, close enough to stable for most of us. The extreme nickel and tin nuclides, while more stable than many, are not very stable. Gah4 (talk) 23:16, 8 April 2019 (UTC)
thread_title:  double magic 

message: Looking over this article, a number of rather minor mistaken terminology uses, omissions, and inconsistencies are noticeable throughout.  I just added 56Ni to the list of doubly magic nuclei (see discussions above as to whether this list may really be useful), but it was strange to see the exotic species 48Ni and 78Ni without the long-known 56Ni in such a list.  "Double magic" seems less preferred than "doubly magic" in the literature (a quick internet search for nuclear physics shows more than five times the results for the latter than the former).  4He is called "most abundant (and stable)" lending a superlative to a binary fact of beta-stability ("tightly-bound" would be correct, but "most stable" is not sensible).  Another misleading term is "proton-rich isotope" which is a misnomer; an isotope is defined (in part) by its proton number; therefore, while "neutron-rich isotope" and "neutron-deficient isotope" are sensible terms, "proton-rich isotope" is not meaningful (e.g., all isotopes of nickel have 28 protons by definition).  48Ca is (as noted above) not in fact stable, but very long lived (in contrast to what is here).  Contrast this with 208Pb, which is stated as "the heaviest stable nuclide"; while in fact true, 209Bi is very long lived which leads to an inconsistency for the treatment of long-lived isotopes.  The lone (and incomplete paragraph) on hassium feels rather biased (considering other omissions) and hence out of place over a decade after its discovery; note that the article does not delve into the concept of shifting magic numbers far from stability, and as it stands the article does not support Z=108 nor N=162 as magic numbers.  I would like to clean up these points in a few weeks' time, if there is no extended discussion to oppose these wide-ranging but relatively simple updates.  DAID (talk) 20:04, 14 May 2019 (UTC)
thread_title:  Nomenclature and mistakes 

message: This is a Compound (linguistics) and has an etymology. Catchpoke (talk) 15:33, 12 July 2021 (UTC)
thread_title:  Etymology