Angular Momentum (Modern Physics)

AI Thread Summary
The discussion centers on calculating the angular momentum values for a hydrogen atom in the n = 3, l = 2 state. For part (a), the possible values of j are determined to be 5/2 and 3/2. In part (b), the total angular momentum magnitudes are calculated using the formula J = sqrt(j(j+1)), yielding results of sqrt(35)/2 hbar and sqrt(15)/2 hbar for j values of 5/2 and 3/2, respectively. Part (c) identifies the possible z components of total angular momentum, with mj values of ±3/2, ±1/2 for j = 3/2 and ±5/2, ±3/2, ±1/2 for j = 5/2. Overall, the calculations appear correct, but the user expresses uncertainty, particularly regarding part (b).
roeb
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Homework Statement


This problem is giving me a headache and unfortunately I can't find any example that is similar to it.
A hydrogen atom is in the n = 3, l = 2 state.

(a) What are the possible values of j?

(b) What are the possible values of the magnitude of the total angular momentum including spin?

(c) What are the possible z components of the total angular momentum?


Homework Equations





The Attempt at a Solution



(a)
I believe that jmax = l + 1/2
and jmin = l - 1/2 so...
jmax = 5/2
jmin = 3/2
so
j = 5/2, 3/2

(b)

J = L + S
J = sqrt( j (j+1) )

J1 = sqrt(35)/2 hbar --> (j =5/2)
J2 = sqrt(15)/2 hbar --> (j=3/2)


(c)

j = 3/2; mj = +- 3/2, +- 1/2
j = 5/2; mj = +-5/2, +-3/2, +-1/2


I am very unsure about this whole process. My book unfortunately doesn't have any examples of this process. Can anyone check my work and see if what I am doing is correct? In particular I am very unsure of part b, it just seems a bit strange to me despite following the formula.

Thanks
roeb
 
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it all looks correct!
 
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