Depth of a finite square potential problem

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Homework Help Overview

The problem involves a finite square-well potential with a specified width and mass, seeking to determine the necessary depth to accommodate three energy levels. The context is rooted in quantum mechanics and potential wells.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss various formulas related to energy levels and penetration density, with some suggesting the use of approximations for energy in an infinite well. Others propose plotting functions to find the minimum potential depth required for three states.

Discussion Status

The discussion is active, with multiple participants offering different perspectives on how to approach the problem. Some guidance has been provided regarding the use of specific equations and methods, but no consensus has been reached on a single approach.

Contextual Notes

There is a mention of the problem not being introductory physics, indicating a level of complexity that may influence the assumptions and methods discussed.

aglo6509
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Homework Statement



Consider a finite square-well potential well of width 3.00x10-15 m that contains a particle of mass 1.88 GeV/c2. How deep does the well need to be to contain three energy levels?

Homework Equations


The Attempt at a Solution



I think I have to use the formula for penetration density:

δx=(hbar)/(sqrt(2m(V0-E)))
V0=0 because the particle is inside the well.

Would I use:

En=(n-1/2)(hbar)ω to find the energy of three levels?

Then would I plug this formula back into the penetration density formula to find the penetration density?

Thank you.
 
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You know how the bound-state energy levels are calculated right?

The third bound state will be the second symmetric state.
So why not use the standard parameterization?

Plot y=v\tan v - the value of v where the second curve hits the v axis is the minimum value of u_0 to contain 3 states, and:
u_0^2 = \frac{mL^2V_0}{2\hbar}


Don't think this counts as introductory physics though.
 
I believe you need to approximate the energy as if it were in an infinite well:

E=n2(hbar2)(π2)/(2mL2)

with n=3
 
@aglo6509: how did you get on? As you see, you are attracting attention 8 months later ;)
@markovcy: welcome to PF; it is nice of you to start out by answering questions.
Under "get posts" at the top, there is an option to look for recent posts that have yet to be replied to - just saying.
 

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