# Neutron quantum numbers (NEED HELP!)

## Main Question or Discussion Point

hi there, friends of physics, could anybody help me? All we know that electrons have 4 quantum numbers that describe them and -as the Pauli exclusion principle said- it can´t exist two electrons with the same quantum numbers. But I have a question, does protons and neutrons have quantum numbers? and, if they have, how do I calculate them?

thanks a lot!

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malawi_glenn
Homework Helper
The quantum numbers and how you evaluate depends on what system you have, what kind of potential you have etc.

hi, glenn, thanks a lot for your answer, but, sorry I dont understand...I need to calculate the quantum numbers of an atom of Uranium 238, how may I do?

malawi_glenn
Homework Helper
And I dont understand your question.

Please write down the exact formulation of your problem/question and what kind of course it is (is it Nuclear physics? then we call is the Nucleus U-238, not atom).

Is it about the shell model? Is it about the Nilsson model?

Quantum numbers is assigned to quantities that are constants of motion.

If this is course work / homework question this thread will be moved to the Home work section and you must provide an attempt to solution.

oh, excuse me -I'm spanish and have some problems with english-
the course is nuclear physics, I have calculated the quantum numbers of all the electrons of the shells (n,l,m and s)and it's agree with the Pauli principle, but I have now to know what kind of differences are behind the protons and neutrons of the nucleus (if the principle is right, all the protons should have different quantum numbers) and the same for the neutrons. Correct me if I'm wrong

thanks a lot for your patience!

malawi_glenn
Homework Helper
protons and neutrons are not indistinguishable fermions, so a proton can have the same Q# as a neutron, was that the answer you was after?

malawi_glenn
Homework Helper
and also since you are new here.

i) ask questions in the correct sub forum and follow the forum rules

ii) The more general the question is, the less probable is it that you are gonna get an answer. Ask as specific questions as possible.

mmm...for example, in the U238 atom:
whats the difference betwen an e- with the Q#(1,0,0,1/2) and other e- with (6,2,0,1/2)?,that the first is in the first shell, with an orbital of a s shaped and the second e- is the last, in the 6#shell and with a d shaped orbital. and now, what's the difference betwen a proton of the nucleus of U238 and other proton of the same nucleus? example: p+(1) ---->Q#(?,?,?,?) and p+(92) ----->Q#(?,?,?,?)

thanks!

under what i have learnt and studyed there is spin and magnetic moment for the proton and neutron .
but i am not sure how to calculate it is value but because electron and protons and neutrons are fermions they must have the same calculation with differnt in the potential due to the nuclear dimension of the nucleus and the electron cloud.
spin quantum numbers of s=1/2 that means spin angular momenta S of magnitude same to the equation of the electron

and spin magnetic quantum number of +-1/2 and as you want U-238
but under the fermion similarity the other quantum numbers can be calculated as well as spn magnetic momenta

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so, abdullah, you mean that the Q# of all the 92p+ of the nucleus should be the following:
p+(1)--->(?,?,0,1/2)
p+(2)--->(?,?,0,-1/2)
p+(3)--->(?,?,1,1/2)
p+(4)--->(?,?,1,-1/2)
.
.
.
p+(92)--->(?,?,?,-1/2)

don't you?, and the neutrons

n(1)--->(?,?,0,1/2)
n(2)--->(?,?,0,-1/2)
n(3)--->(?,?,1,1/2)
n(4)--->(?,?,1,-1/2)
.
.
.
n(146)--->(?,?,?,-1/2), is it right?
the Q# n and l mean the shell and the orbital shape, what kind of numbers could mean in a p+ or a n?

thanks a lot!!

malawi_glenn
Homework Helper
m4730: The differences between the protons in a nucleus must be their quantum numbers.

Now what are your original problem? "Assign nuclear spin to the nucleus U-238" ?

no, the problem is how to assign quantum numbers to the neutrons and protons in a nucleus of U238, should I use the same way I used to assign to the e-?, ex: (1,0,0,1/2),(1,0,0-1/2),(2,0,0,1/2),(2,0,0,-1/2),(2,1,-1,1/2)...sorry if a can't explain myself better, but that`s the original problem

malawi_glenn
Homework Helper
You can't do the same way since l and n is not related in the same way in atomic physics as in nuclear physics. You should look up how the Nuclear Shell model is worked out.

so, m and s can be expressed in the way of the #10 post?

malawi_glenn
Homework Helper
no

$$m_l$$ for l's projection
and
$$m_s$$ for s's projection

The quantum numbers that you have now is n,l,m_l and m_s

In atomic physics, l = any value of n -1, i.e if n = 2; l can be 1 or 0

Now in the nuclear shell model, there is no restriction on l vs. n.
Each n can have any l as you wish, and the energy levels are more complex, since the energy depends on the m_s quantum number.

You should look at the nuclear shell model in your text book or lecture notes.