Energy levels for a 3D cubical box

In summary, the problem involves finding the energies of the second, third, fourth, and fifth levels for the three-dimensional cubical box and determining which of these levels are degenerate. The equation used for this problem is E = h^2/8mL^2 (n^2 sub x + n^2 sub y + n^2 sub z), where nx, ny, and nz are positive integers. The ground state is represented by (1,1,1) and the first excited state is represented by (1,1,2). The second excited state could be either (1,2,2) or (1,1,3).
  • #1
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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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  • #2
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?
 
  • #3
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)?
 

Related to Energy levels for a 3D cubical box

1. What is a 3D cubical box?

A 3D cubical box is a theoretical model used in quantum mechanics to describe the behavior of particles confined in a three-dimensional space. It is represented as a cube with finite dimensions, and the particles are considered to be trapped within the walls of the box.

2. How are energy levels determined in a 3D cubical box?

The energy levels in a 3D cubical box are determined by solving the Schrodinger equation, which is a mathematical equation used to describe the behavior of quantum particles. The solutions to this equation give the allowed energy levels for the particles within the box.

3. What is the significance of energy levels in a 3D cubical box?

The energy levels in a 3D cubical box represent the different states that particles can have within the box. These levels determine the probability of finding a particle in a specific energy state, and they also affect the overall behavior and properties of the system.

4. How do the dimensions of the box affect the energy levels?

The dimensions of the box play a crucial role in determining the energy levels. As the dimensions of the box increase, the energy levels become more closely spaced, and the number of energy levels also increases. This is because a larger box allows for more possible positions and velocities of the particles, resulting in a greater variety of energy states.

5. Can energy levels in a 3D cubical box have negative values?

No, the energy levels in a 3D cubical box cannot have negative values. This is because the energy of a particle in a confined space must be positive, as it represents the minimum amount of energy required to keep the particle within the box. However, the energy levels can have a zero value, which is known as the ground state.

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