Quantum numbers in wikipedia's table

In summary, the conversation discusses the quantum numbers with spin-orbit interaction and focuses on the table provided in the Wikipedia page. The question is raised about the presence of dashed values in the table and why "l-s" is dashed when it should equal 1/2. The conversation then delves into the rules for the projection of total angular momentum and the contradiction in the table. The conversation concludes with a clarification that there may be a typo in the rule regarding the modulus of mj. Overall, the conversation highlights the confusion and potential errors in the table and rules regarding quantum numbers with spin-orbit interaction.
  • #1
fluidistic
Gold Member
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I don't understand why there are 2 dashed values in this table: http://en.wikipedia.org/wiki/Quantum_number#Quantum_numbers_with_spin-orbit_interaction.
I have that [itex]j=l+s,l+s-1,...,|l-s|[/itex]. So let's take #1 of the table.
They give l=1 and we know that [itex]s=1/2[/itex]. Thus [itex]j=l+s=3/2[/itex] or [itex]j=l-s=1/2[/itex]. Why is l-s=1/2 dashed?!
The same question appears for #6.
 
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  • #2
It violates the rule from

The projection of the total angular momentum along a specified axis (mj = −j, −j + 1, …, j), which is analogous to m, and satisfies mj = mℓ + ms where |mℓ + ms| < j.

(also on the webpage you referenced).
 
  • #3
dextercioby said:
It violates the rule from

The projection of the total angular momentum along a specified axis (mj = −j, −j + 1, …, j), which is analogous to m, and satisfies mj = mℓ + ms where |mℓ + ms| < j.

(also on the webpage you referenced).

Ok thank you. But I am confused. They say that mj goes from -j to j via integers. And then that the modulus of mj must be strictly smaller than j. Thus how can mj be worth j?
 
  • #4
Ah nevermind, I understood. In that example, if j=1/2, you can't get an mj=3/2 because if j=1/2 then mj=-1/2 or 1/2.
But shouldn't they say [itex]|m_l+m_s| =|m_j| \leq j[/itex] rather than < j?
 
  • #5
Yes, now that I think about it, it should include equality, too. Typo, maybe.
 
  • #6
Ok thank you very much!
 

1. What are quantum numbers?

Quantum numbers are a set of numerical values that are used to describe the characteristics of an electron in an atom, such as its energy, orbital shape, and orientation in space.

2. How many quantum numbers are there?

There are four quantum numbers: the principal quantum number, the azimuthal quantum number, the magnetic quantum number, and the spin quantum number.

3. What does the principal quantum number represent?

The principal quantum number, denoted by "n", represents the energy level or shell that an electron occupies in an atom. It can have any positive integer value starting from 1.

4. What is the significance of the azimuthal quantum number?

The azimuthal quantum number, denoted by "l", represents the subshell or orbital shape of an electron. It can have values ranging from 0 to n-1, where n is the principal quantum number.

5. How does the magnetic quantum number relate to the orientation of an electron?

The magnetic quantum number, denoted by "ml", represents the specific orbital or spatial orientation of an electron within a subshell. It can have values ranging from -l to +l, including 0.

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