What Are the Energy Levels and Degeneracies for a 3D Cubical Box?

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SUMMARY

The energy levels for a three-dimensional cubical box can be calculated using the formula E = h²/8mL² (n²ₓ + n²ᵧ + n²𝓏). The second, third, fourth, and fifth energy levels correspond to the quantum numbers (1,1,2), (1,2,2), (2,2,1), and (2,1,2) respectively. The degeneracies occur when different combinations of quantum numbers yield the same energy level, such as (1,2,1) and (2,1,1) both resulting in the same energy value of 6. The ground state is (1,1,1) and the first excited state is (1,1,2).

PREREQUISITES
  • Understanding of quantum mechanics principles
  • Familiarity with the concept of energy levels in quantum systems
  • Knowledge of quantum numbers and their significance
  • Ability to apply the formula for energy levels in a 3D box
NEXT STEPS
  • Study the derivation of the energy levels for a 3D infinite potential well
  • Learn about quantum degeneracy and its implications in quantum mechanics
  • Explore the significance of quantum numbers in determining energy states
  • Investigate the differences between 1D, 2D, and 3D quantum boxes
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Students and educators in quantum mechanics, physicists studying particle confinement, and anyone interested in the mathematical modeling of quantum systems.

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Homework Statement


Find the energies of the second, third, fourth, and fifth levels for the three-dimensional cubical box. Which are degenerate?


Homework Equations


E = h^2/8mL^2 (n^2 sub x + n^2 sub y + n^2 sub z)


The Attempt at a Solution


The levels would be degenerate if one of them occupied two or more different states, or if two occupied the same state, correct?

I'm lost on what to use for n_subx, n_suby, and n_subz in the problem. I'm pretty sure it's not Pythagorean
 
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I've found that (1,1,1) = 3, (1,1,2) = 6

and 6 is degenerate since it could be (1,2,1) or (2,1,1).

But do these correspond to n = 3 and n = 6?
 
nx, ny and nz are positive integers, so 1, 2, 3,...

Clearly (1,1,1) is the ground state, and (1,1,2) is the first excited state. What's the second one? Is it (1,2,2) or (1,1,3)?
 

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