Talk:Halo nucleus

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References[edit]

WTF? What is the point of including the link http://www.sciencemag.org/cgi/content/full/286/5437/28?ck=nck -- which requires a login -- in the References section? 203.109.213.221 (talk) 10:49, 10 February 2008 (UTC)

I agree with this comment, and have taken the appropriate action: completely deleting that reference. I also fixed the two *actual* references so that they would be references instead of just external links. I left the existing other three URLs that load, although it is not made clear exactly what they correspond to in the article, just that someone used them as references at some point. Zaphraud (talk) 02:11, 16 March 2009 (UTC)

How many nucleons in the halo?[edit]

14Be: four-neutron halo ??? 14Be is a two-neutron halo (12Be + n + n) 142.90.108.17 (talk) 20:00, 25 June 2008 (UTC)

The above comment raises the question of whether there is a simple way to predict how many nucleons are in the halo? I would expect some simple recipe based on the shell model, analogous to the prediction of electron configurations for atoms in chemistry. Could someone who knows nuclear physics include the recipe used here with an example or two?

I also looked at the abstract of the reference given for 14Be, and note the words "Our calculation indicates that the 12Be(g.s.)+n+n configuration represents 66% only of the total wave function, and that core excitations cannot be neglected." So configuration interaction is important at least in this case, and it would be helpful to provide an assessment of the accuracy of one-configuration descriptions such as a two-neutron halo or a four-neutron halo. Dirac66 (talk) 17:00, 22 June 2009 (UTC)

The article doesn't have enough about the 4Be14 nucleus to permit much of a comment. But consider the information about 3Li11. If you start out with 3Li11 you have a CRC reported half life of 8.8 ms before half of the nuclei have changed to 4Be11 via electron emission. So by approximately .1 seconds there is no more 3Li11 but rather 4Be11, which has a has a reported half life of 13.8 seconds. And 4Be11 is described as a single neutron halo nuclide. So we have less than .1 seconds for 3Li11 to not change to 4Be11 and to create a 2nd neutron halo and what's the probability of that? In the meantime we have the nuclide 4Be11 which is declared to be a single neutron halo nuclide and what is the probability that some of that could become a double neutron halo neutron nuclide? For the approximately 13.8 second time of existence before the nuclide becomes 5B11 approximately 13.7 of it is spent as 4Be11, so how do we know that the double neutron halo occurrence occurred in the initial <.1seconds? I would guess that they have some additional evidence about the decay properties of 4Be11; but because it only has a 13.8 second half life, an ion beam test of pure 4Be11 might be difficult.WFPM (talk) 00:51, 5 August 2009 (UTC)
Re the radiation saga of the A=14 nucleus, we have the CRC reported 4Be14 nucleus with a 4.6 ms half life, decaying to 5B14, with a 14ms half life and then to 6C14, with a 10E11s (5715y) half life before stable 7N14. So after a fraction of a second, the nucleus is converted first to 5B and then to 6C,and wouldn't actually be a Be nucleus. So how it comes up as 4Be12 plus 2 extra halo neutrons is not understood. But it would only be possible before the first beta conversion, which brings up the question of how it was created in the first place.WFPM (talk) 09:30, 8 August 2009 (UTC)—
If these people are good at evaluating the proton acquiring properties of the elements, I would think they would be interested in the element 46Pd, where it is speculated that is possible to acquire an additional proton by the so called "cold fusion" process. Or, add a proton to 3Li7 to make 4Be8. If that were possible, it might solve a lot of technical difficulties we're having in nuclear fusion technology.WFPM (talk) 10:11, 8 August 2009 (UTC)

wait, what?[edit]

The article states: "Several nuclides have a halo in the excited state but not in the ground state."

Doesn't this mean that a purely chemical condition has the potential to effect a purely nuclear condition, perhaps such as half-life? I'd like to see more about this. Zaphraud (talk) 02:11, 16 March 2009 (UTC)

In this article, excited state refers to its nuclear state, not its chemical state. The difference is that an excited chemical state refers to an extra-energetic electron orbital configuration, wheras an excited nuclear state refers to the high-energy configuration of nucleons in the nucleus. One of the most prominent examples of this is Am242m (half life ~ 100yrs) versus Am242 (half life ~100days). 24.124.54.30 (talk) 02:32, 13 May 2009 (UTC)
This brings up the problem of how to know what the energy level of the ground state really is. This is with reference to certain EE nuclides (such as EE84Po210), which are declared to be 100% alpha particle emitters with a 138 day half life. Has anybody ever looked in the debris of yellowcake, or some other depleted 4n+2 nuclide to see if they can find any trace of 84Po210?WFPM (talk) 16:07, 21 August 2009 (UTC)PS And don't look with a radiation detector, ala the Curies, because what is looked for is a stable isotope, and not a radioactive one.WFPM (talk) 16:18, 21 August 2009 (UTC)
Let's consider the isotope Am242, but let's call it OO95Am242. That means that it is an odd Z isotope with an odd number of Neutrons (147) but with an even number of extra neutrons(52). Its composition formula is therefor A = 3Z-43, which is not a good number with relation to stability indications. And it has two reported ways to correct it's structure towards a condition of stability.WFPM (talk) 16:50, 21 August 2009 (UTC)From the ground state the Nubase data shows it going 82.7% to EE96Cm242 and 17.3% to EE94Pu242. However, its condition of stability is such that 9% of it will fission with an extra low energy excitation and 100% will fission with high excitation. However it is less stable than OE95Am241, with only 51 extra neutrons and a formula of A=3Z-44. So the last neutron made it less stable. And I don't see how the electron configuration had anything to do with this, unless they are involved in the excitation of the atom.WFPM (talk) 01:44, 22 August 2009 (UTC)

Table typo[edit]

This table lists the halo isotope of Phosphorus as Carbon-26... --207.230.130.227 (talk) 20:51, 30 April 2010 (UTC)

Actual size of the nuclear halo[edit]

The article gives a formula for the typical radius of a nucleus and states that nuclei that have a halo are "appreciably larger". It would be very useful to include in the isotope table their measured and predicted size (if such data is available), so that a comparison can be made. --Doctor C (talk) 17:04, 3 March 2012 (UTC)

Halo size of Li-11[edit]

When discussing Li-11, the article mentions that the cross-section is 3.16fm. Cross-section is usually measured in barns, and is a measurement of area. Does the author instead mean the radius of the nucleus? If so, what kind of radius is it, and from where was the value sourced? Seantellis (talk) 15:12, 3 February 2014 (UTC)