Quantum numbers in wikipedia's table

Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
5 replies · 2K views
fluidistic
Gold Member
Messages
3,934
Reaction score
286
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.
 
Physics news on Phys.org
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).
 
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?
 
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?
 
Ok thank you very much!