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

Click For Summary
SUMMARY

The discussion centers on the measurement of total orbital angular momentum for a hydrogen atom in a 3px state. The quantum numbers for this state are n = 3, l = 1, and m = -1, 0, +1. Participants clarify that the expectation value of L^2 for this state can be calculated, but the integral ∫Ψ*L^2Ψdτ is complex. It is concluded that while the average value over multiple measurements may seem to trend towards zero, the p_x orbital has a definite m_l value, which affects the outcome.

PREREQUISITES
  • Understanding of quantum mechanics principles, specifically angular momentum.
  • Familiarity with hydrogen atom wavefunctions and quantum numbers.
  • Knowledge of the mathematical operations involving integrals in quantum mechanics.
  • Concept of commutation relations in quantum mechanics, particularly between Hamiltonian and angular momentum operators.
NEXT STEPS
  • Study the properties of angular momentum operators in quantum mechanics.
  • Learn how to calculate expectation values for quantum states using integrals.
  • Explore the significance of quantum numbers in determining the behavior of atomic orbitals.
  • Investigate the commutation relations between different quantum operators, focusing on L^2 and the Hamiltonian.
USEFUL FOR

Students and educators in quantum mechanics, physicists analyzing atomic structures, and anyone interested in the mathematical foundations of angular momentum in quantum systems.

mordacious
Messages
2
Reaction score
0
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
 
Physics news on Phys.org
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).
 

Similar threads

  • · Replies 21 ·
Replies
21
Views
2K
Replies
4
Views
2K
Replies
1
Views
2K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 0 ·
Replies
0
Views
2K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 32 ·
2
Replies
32
Views
4K
  • · Replies 3 ·
Replies
3
Views
5K