Understanding the Unbound Nature of the nn-Pair in Nuclear Clusters

In summary, someone who has studied nuclear physics and knows about the isospin constraint and how the nn-pair is unbound would be able to help you understand why the nn-pair is unbound.
  • #1
malawi_glenn
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Why is the nn-pair unbound? I don't seem to find the answer in any of my textbooks =/
 
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  • #2
Why is the nn-pair unbound?

What do mean by "unbound"? If you are wondering why there is no such entity as a double neutron, there is nothing to hold two neutrons together.
 
  • #3
That was a very good answer, not. Do you think I am that noob on physics that I have not figured it out my self? Saying that something is unbound and "there is nothing that can hold it togheter" is pretty much saying the same thing.

Someone who has studied nuclear physics who can help me? mathman seems to be a retired mathematician..

I was thinking that neutron + neutron has isopspin 1 and the deutron (the bound state of neutron + proton) has isospin 0. So does it has something to do with that?
 
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  • #4
To malawi_glenn:

While it is true that N-N pair is not "bound" in free state (as you say due to isospin constraint), this does not mean it does not exist as a nucleon cluster state in isotopes as a type of resonance:

1. The di-neutron (N-N) was suggested as a cluster structure moving around some isotopes as long ago as 1969 by L. Pauling:
http://www.pnas.org/cgi/reprint/64/3/807.pdf

2. Di-neutron cluster structure has recently been suggested in He-8 isotope (see page 8 for explanation of what is means to say N-N cluster may exist):

http://arxiv.org/PS_cache/arxiv/pdf/0707/0707.2120v1.pdf

and here for He-8:
http://www.ujp.bitp.kiev.ua/papers/460302p.pdf[/URL]

3. Also for He-6:
[PLAIN]http://www.maik.ru/abstract/nuclphys/0/nuclphys10_0p1724abs.htm[/URL]

4. Di-neutron cluster predicted in O-18 isotope:

http://prola.aps.org/abstract/PRC/v16/i1/p475_1

5. Di-neutron long ago was predicted to be a by-product of certain fission events:
[url]http://www.nature.com/nature/journal/v165/n4201/abs/165722a0.html[/url]
but I have no idea if the experiments suggested have been conducted.

6. See also "halo nuclei" literature:

http://theory.gsi.de/hirschegg/2003/Proceedings/Al-Khalili_131.227.115.66_alkhalili.pdf
[PLAIN]http://www.ingentaconnect.com/content/maik/10637788/2000/00000063/00000010/00000965[/URL]

Hope these links are of some use to you.
 
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  • #5
Thanx, yes they can exists in cluster. But I was reffering to the analogy with the deutron only.

Thanx again, will look at the links :D
 

1. Why do some nn-pair molecules remain unbound?

Nn-pair molecules remain unbound because they lack the necessary energy to form a stable bond. This could be due to a variety of factors, such as the distance between the particles, the strength of the attractive forces between them, or the presence of other molecules that interfere with bonding.

2. What causes nn-pair molecules to become unbound?

Nn-pair molecules can become unbound due to a change in conditions, such as an increase in temperature or pressure. This can disrupt the balance between attractive and repulsive forces, causing the molecules to separate.

3. How can we predict whether an nn-pair molecule will remain bound or become unbound?

Predicting whether an nn-pair molecule will remain bound or become unbound requires a thorough understanding of the forces at play between the particles. Factors such as the distances between the particles, their relative masses, and the strength of their interactions must all be considered.

4. Can we control whether an nn-pair molecule remains bound or not?

In some cases, it is possible to control whether an nn-pair molecule remains bound or not. This can be achieved through manipulating the external conditions, such as temperature or pressure, or by introducing other molecules that can interact with the nn-pair molecules and affect their bonding.

5. Are there any practical applications for studying unbound nn-pair molecules?

Studying unbound nn-pair molecules can provide valuable insights into the fundamental forces that govern molecular interactions. This knowledge can be applied in various fields, such as materials science, drug discovery, and nanotechnology, to develop new technologies and improve existing ones.

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