What is L^2Ψ for a 3px state of a H-atom?

AI Thread Summary
In the discussion about measuring the total orbital angular momentum of a hydrogen atom in a 3px state, participants clarify the quantum numbers associated with this state: n = 3, l = 1, and m = -1, 0, +1. The focus shifts to the expectation value of L^2, with one participant suggesting that averaging the measurements would yield zero due to the contributions from different m values. However, another member points out that the p_x orbital has a definite m_l value, implying that the earlier assumption about averaging might be incorrect. The integral calculation for L^2Ψ is deemed unnecessary, as the Hamiltonian and L^2 commute for the hydrogen atom, simplifying the analysis. The discussion emphasizes the importance of understanding the quantum mechanical properties of the state rather than just performing calculations.
mordacious
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Awesome forum here!

I'm stuck on a homework problem and need some guidance.

A H-atom exists in a 3px state. What would be the result of measuring the total orbital angular momentum of this state (e.g. 100 measurements)?

I assume when they say 100 measurements that they mean the expectation value? If so there is now the problem of which wavefunction to use as a 3px state has three due to m = -1, 0, +1. I remember something about how orbitals in the same subshell can be combined but I can't find it in my notes and I'm not sure if this is what I'm looking for.

Anyways, even if I just choose one randomly, finding ∫Ψ*L^2Ψdτ is a huge task.

Am I just going about this all wrong?

Thanks,
Ashley
 
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What is a 3px state ? What quantum numbers does it have ?
 
dextercioby said:
What is a 3px state ? What quantum numbers does it have ?

n = 3
l = 1
m = -1, 0, +1

I'm starting to think this is more of a thinking question than a calculation question. If 3p-1 and 3p+1 give one value and 3p0 gives 0 then over 100 measurements the average value would be 0. Does this sound logical?

Ashley
 
As far as i know, the p_x orbital has a definite value of "m_l". So your last answer is wrong.
 
It wouldn't matter if the eigenvalues of L^2 don't depend on m. So do they?

Doing the integral looks like a fun exercise, but it's not necessary. What is L^2Ψ? (Hint: H and L^2 commute for the H-atom).
 
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