What Determines the Spin and Parity of a Nucleus with Multiple Excited Nucleons?

In summary, the spin and parity of a nucleus is determined by looking at the unpaired nucleon in the outermost shell. In the case of a lithium-7 nucleus with two excited protons, the spin would be (1/2)^+ and the parity would be negative, since the outermost nucleon has a j value of 1/2 and l=0. All unpaired nucleons, including those in excited states, contribute to the spin and parity of the nucleus.
  • #1
stunner5000pt
1,461
2
I understand that the spin and parity of the nucleus is determined by looking at hte unpaired nucleon (is that the correct way of saying it?). But what if we were looking at nulceus where 2 or more nucleons were excited from the ground state?? What would the spin and parity of the nucleus be, then??

What if we had a lithium-7 (Z=3) nucleus, say where the a proton from [itex] 1s_{1/2} [/itex]was excited (by some means) to the [itex] 2s_{1/2} [/itex] state. Now we have 2 unpaired protons, one in the [itex] 1p_{3/2}[/itex] state and the [itex] 2s_{1/2} [/itex]

what would the spin and the parity of this nucleus be??

Do we still look at the unpaired nucleon in teh outermost shell only??
In this case, then the spin would be [itex] (1/2)^+ [/itex], since the j value of the outermost nucleon in 1/2 and l=0.

(Spin and parity is given by [itex] i^{\pi} [/itex]
where i=j
and [itex] \pi = (-1)^l [/itex])
 
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  • #2
Old stuff, but let's give an answer: All unpaired nucleons contribute to spin and parity, that is ALL three protons. Smallest possible spin is 1/2 and highest 5/2. Parity is evidently negative (1s and 2s protons contribute nothing, the p proton contributes negative).
 

1. What is nuclear spin and parity?

Nuclear spin and parity are two properties that describe the internal structure of atomic nuclei. Spin refers to the intrinsic angular momentum of the nucleus, while parity refers to its symmetry under spatial inversion.

2. How are nuclear spin and parity measured?

Nuclear spin is measured using spectroscopic techniques, such as nuclear magnetic resonance (NMR) or electron spin resonance (ESR). Parity can be determined by studying the decay products of a nucleus.

3. What is the significance of nuclear spin and parity?

Nuclear spin and parity are important for understanding the behavior and interactions of atomic nuclei. They can also provide information about the nuclear forces and structure of a nucleus.

4. How do nuclear spin and parity affect nuclear reactions?

Nuclear spin and parity can influence the selection rules for nuclear reactions, determining which reactions are allowed and which are forbidden. They can also affect the energy levels and stability of a nucleus.

5. Can nuclear spin and parity change over time?

Yes, nuclear spin and parity can change through certain nuclear processes, such as beta decay or nuclear reactions. However, these changes are typically small and do not affect the overall properties of the nucleus.

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