What is the Nuclear Spin of Fluorine-19 and How is it Calculated?

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Discussion Overview

The discussion centers on the nuclear spin of Fluorine-19 and the methods used to calculate it, particularly through the nuclear shell model. Participants explore the implications of odd and even nucleon configurations and their contributions to nuclear spin.

Discussion Character

  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant calculates the nuclear spin of Fluorine-19 as I=5/2 based on the configuration of the nucleons, specifically citing the odd proton in the 1d5/2 orbital.
  • Another participant challenges this calculation, asserting that the nuclear spin should be I=1/2, as it is determined by the unpaired proton, and clarifies the distinction between total angular momentum and nuclear spin.
  • A third participant expresses confusion regarding the previous explanations and provides an example of Scandium-43, suggesting that the nuclear spin should be I=1/2 but is listed as I=7/2, referencing the same source.
  • Another participant proposes a model of Fluorine-19 as an Oxygen-18 nucleus plus an additional proton, concluding that this leads to a nuclear spin of 1/2.
  • One participant questions the understanding of the difference between net spin and total magnetic moment, indicating a potential misunderstanding in the discussion.

Areas of Agreement / Disagreement

Participants express differing views on the calculation of nuclear spin for Fluorine-19, with no consensus reached on the correct value or methodology. Multiple competing interpretations of the nuclear shell model and its implications for nuclear spin are evident.

Contextual Notes

Participants reference specific nucleon configurations and their contributions to nuclear spin, but there are unresolved assumptions regarding the definitions of spin and angular momentum in nuclear physics.

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I was trying to calculate the ##^{19}_{9}F_{10}## nuclear spin using the nuclear shell method. From what i know the nuclear spin for a nucleous with odd ##A## is the total angular momentum ##J## of the stand-alone nucleon:
P: ##(1d_{5 \backslash 2})^1## (stand-alone nucleon)
N: ##(1d_{5 \backslash 2})^2##
which in this case is a proton with ##J=\frac{5}{2}## so it leads to a nuclear spin of ##I=\frac{5}{2}##. But this isn't what i found in lecture, from the pdg (http://ie.lbl.gov/toi/nuclide.asp?iZA=90019) ##^{19}_{9}F_{10}## result to have ##I=\frac{1}{2}##.
I missed something?
 
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Your filling is incorrect.
You have 9 protons and 10 neutrons. Well no need to care about the neutrons, since they will pile up into pairs together (even number). From the protons you will have 1 extra remaining unpaired. You will fill until 1d_{5/2} . So your nucleus spin will be determined by the unpaired proton, the proton has spin 1/2 so 1/2 is the spin of your nucleus...<br /> Sometimes things are mixed with J, S in nuclear physics, calling both of them "spins". The total angular momentum is indeed 5/2, the spin is 1/2.
 
Last edited:
ChrisVer said:
Your filling is incorrect.
You have 9 protons and 10 neutrons. Well no need to care about the neutrons, since they will pile up into pairs together (even number). From the protons you will have 1 extra remaining unpaired. You will fill until 1d_{5/2} . So your nucleus spin will be determined by the unpaired proton, the proton has spin 1/2 so 1/2 is the spin of your nucleus...<br /> Sometimes things are mixed with J, S in nuclear physics, calling both of them "spins". The total angular momentum is indeed 5/2, the spin is 1/2.
<br /> <br /> My apologies but I'm not understanfding what you mean, for example take the ##^{43}_{21}Sc_{22}##. It have 22 neutron (so we don't need to care about), and 21 proton which are filled until ##1f_{7 \backslash 2}##. There's only one proton unpaired so nuclear spin ##I## should be ##\frac{1}{2}## (equal to the spin of the proton) but is ##I=\frac{7}{2}## (always from pdg <a href="http://ie.lbl.gov/toi/nuclide.asp?iZA=210043" target="_blank" class="link link--external" rel="nofollow ugc noopener">http://ie.lbl.gov/toi/nuclide.asp?iZA=210043</a>)
 
I don't understand what either of you is saying. 19F can be modeled as an 18O plus a proton. 18O is 0+, so 19F is 1/2+.
 
have you failed to recognize the difference between net spin and total magnetic moment?
 

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