Infinite Quantum Well: E2-E1, Wavefunction, Energy

grothem
Messages
21
Reaction score
0

Homework Statement


An infinite quantum well width is 5 nm. An electron is confined in the well with 50% in the lowest eigenstate E1 and 50% in the second lowest state E2.
1. What is the energy difference between the two lowest states, E2-E1
2. What is the possible wavefunction of the electron
3. What is the average energy of the electron
4. When t=(Pi/2)[hbar/(E2-E1)], what is the wavefunction


Homework Equations





The Attempt at a Solution


I know the possible wavefunction could be Psi(x)=Sqrt(.5)Phi1(x) + Sqrt(.5)Phi2(x)
And the average energy, .5E1+.5E2
But I'm not sure where the width of the well comes into play for these equations, unless I'm not on the right track

Also, not sure how to find the difference between the two states
 
Physics news on Phys.org
Both \psi_1(x) and \psi_2(x) depend on the width of the well...what are the expressions for these states?

You should also already be familiar with the energy levels of a particle in a box...what are they?
 
Thread 'Need help understanding this figure on energy levels'
This figure is from "Introduction to Quantum Mechanics" by Griffiths (3rd edition). It is available to download. It is from page 142. I am hoping the usual people on this site will give me a hand understanding what is going on in the figure. After the equation (4.50) it says "It is customary to introduce the principal quantum number, ##n##, which simply orders the allowed energies, starting with 1 for the ground state. (see the figure)" I still don't understand the figure :( Here is...
Thread 'Understanding how to "tack on" the time wiggle factor'
The last problem I posted on QM made it into advanced homework help, that is why I am putting it here. I am sorry for any hassle imposed on the moderators by myself. Part (a) is quite easy. We get $$\sigma_1 = 2\lambda, \mathbf{v}_1 = \begin{pmatrix} 0 \\ 0 \\ 1 \end{pmatrix} \sigma_2 = \lambda, \mathbf{v}_2 = \begin{pmatrix} 1/\sqrt{2} \\ 1/\sqrt{2} \\ 0 \end{pmatrix} \sigma_3 = -\lambda, \mathbf{v}_3 = \begin{pmatrix} 1/\sqrt{2} \\ -1/\sqrt{2} \\ 0 \end{pmatrix} $$ There are two ways...
Back
Top