Atomic Half Lives: Calculating Half Life of an Atom

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Discussion Overview

The discussion revolves around the calculation of the half-life of atomic nuclei, exploring the complexities involved in determining half-lives for various isotopes and the underlying principles governing nuclear stability.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants inquire about the formula for calculating the half-life of atomic nuclei, noting that the formula may depend on specific conditions or information provided.
  • There is a discussion on the complexity of calculating half-lives, particularly for isotopes like radon, neptunium, and ununbium, with one participant emphasizing the need for a solid understanding of theoretical nuclear structure physics.
  • One participant mentions a pattern where nuclei further from the valley of stability tend to have shorter half-lives, suggesting a relationship between stability and half-life.
  • Another participant raises questions about the reasons behind the locations of the valley of instability and the sea of instability, proposing that physical principles dictate the stability of nuclei.
  • There is a reference to beta decay sequences and the concept of binding energy, indicating that the stability of nuclei is influenced by their mass and the arrangement of protons and neutrons.

Areas of Agreement / Disagreement

Participants express varying levels of understanding regarding the calculation of half-lives and the factors influencing nuclear stability. There is no consensus on a specific formula or method for calculating half-lives, and the discussion remains unresolved regarding the underlying principles of nuclear stability.

Contextual Notes

The discussion highlights the complexity of nuclear structure and the need for specific isotopic information when calculating half-lives. Limitations include the dependence on theoretical models and the intricacies of many-body quantum systems.

monkeylx1
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Is there a formula that can be used to find the half life of an atom?
If so, what is it?
 
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monkeylx1 said:
Is there a formula that can be used to find the half life of an atom?
If so, what is it?

half life of an atom?

you mean half life of a nucleus right?

and the formula depends on what you are given...
 
Yeah half life of a nucleus.
I mean, say if you had radon nuclei, neptunium nuclei, and ununbium nuclei, etc. what is the pattern, or how can it (for example) calculate the half life of a unbihexium nucleus?
 
monkeylx1 said:
Yeah half life of a nucleus.
I mean, say if you had radon nuclei, neptunium nuclei, and ununbium nuclei, etc. what is the pattern, or how can it (for example) calculate the half life of a unbihexium atom?

that is very very complicated. I am specalizing in Nuclear structure physics, and calculate half life from just theory is very complicated.

The pattern is how ever that the further away you are from the valley of stability, the shorter half-life.


Atomic nuclei are many body quantum systems with approx 240 particles (these nucleis you stated), so it is very complicated. So if you want to calculate this, you need a good reference on theoretical nuclear structure physics.

Also you must specify what ISOTOPE you are considering.
 
But things in nature always have a reason for being there, a physical principal.
Why are the valley of instability and the sea of instability in those spots?
 
monkeylx1 said:
But things in nature always have a reason for being there, a physical principal.
Why are the valley of instability and the sea of instability in those spots?


Nuclei tends to go towards the most bounded state, which then is the most stable.

See for example this picture, showing you beta decay sequences for mass number A = 76.

http://www.tunl.duke.edu/~hornish/images/a76spec.jpg

The most bounded nuclei with A = 76 is Se-76, and you see two parabolas. The upper one is odd odd (i.e odd Z and odd N), the lower is even-even. The parabolas is the mass of the nucleis, the less mass, the more bound it is (remember the concept of binding energy).

Now the general idea is that depending on who many protons and neutrons you have, you get different potentinal wells, which gives you the number of stable/bound states and HOW stable they are etc. And this is a very complicated thing as I said.. The principle is to minimize the mass, physical systems always tends to go the lowest state physical possible.
 
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