- #1
Potatochip911
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- 3
Homework Statement
An electron in a finite square well has 6 distinct energy levels. If the finite square well is 10nm long determine:
a) Approximate the possible values for the depth of the finite square well ##V_0##.
b) Using a well depth value in the middle of the results obtained from part a) find the energy when the electron is in the ##n=3## state.
c) For the ##n=3## state determine the un-normalized wave function
d)For ##-20nm<x<20nm## draw the ##n=3## wave function
e) For ##-20nm<x<20nm## draw the probability function
Homework Equations
##-\frac{\hbar^2}{2m}\frac{d^2\psi(x)}{dx^2}+V(x)\psi(x)=E\psi(x)##
The Attempt at a Solution
Part a) of the question is somewhat tedious and involves solving transcendental equations, I essentially just followed how they solved it on this site which gave me the the possible range for the depth of the finite square well to be ##V_0=0.0237eV## to ##V_0=0.0333eV##
Now for part b), taking the average of these gives ##V_0=0.0285eV## although I'm not sure how I can use this to find the energy of the electron in the n=3 state. In my textbook they seem to use the equation ##E_n=n^2\frac{\pi^2\hbar^2}{2mL^2}## which doesn't seem to mention the potential at all.
From the plot I've listed the coordinates of the n=3 intersection in case that's useful. The lines are: ##y=-\mbox{cot}(x)##, ##y=\tan(x)##, and ##y=\sqrt{(\frac{8.648}{x})^2-1}## where ##8.648=\mu=L\sqrt{\frac{2m}{\hbar^2}V_0}##
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