Finite Square Well, Ψ[SUB]III[/SUB] const related too Ψ[SUB]II[/SUB]?

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SUMMARY

The discussion centers on solving the wave function continuity conditions for a finite square well as presented in Griffith's Modern Physics, 2nd edition, specifically in chapter 5. The user correctly identifies the relationship between the wave functions ΨI(0) and ΨII(0) and derives C = QA/α. However, confusion arises when attempting to graph the probability distributions for regions I and II, as they do not match at x = 0. The conversation highlights the need for clarity on the boundary conditions and the implications of wave function continuity across the potential well.

PREREQUISITES
  • Understanding of quantum mechanics concepts, specifically wave functions and potential wells.
  • Familiarity with Griffith's Modern Physics, 2nd edition, particularly chapter 5.
  • Knowledge of differential equations as applied to quantum mechanics.
  • Ability to graph mathematical functions and interpret their physical significance.
NEXT STEPS
  • Review the boundary conditions for wave functions in quantum mechanics.
  • Study the mathematical derivation of wave functions in finite potential wells.
  • Learn about the implications of wave function continuity and normalization in quantum systems.
  • Practice graphing wave functions for various potential energy profiles to enhance visualization skills.
USEFUL FOR

Students of quantum mechanics, particularly those studying finite square wells, and educators looking to clarify wave function behavior at boundaries. This discussion is beneficial for anyone seeking to deepen their understanding of wave function continuity and its implications in quantum physics.

The Floating Brain
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Homework Statement
There are two ledges with of U potential energy, and a cavern in between them of 0 potential energy. Such that

U(x) = { x <= 0, U, x > 0, x >= L, U }

Find the probability distribution for all 3 regions
Relevant Equations
(ħ[SUP]2[/SUP]/2m)((d[SUP]2[/SUP]Ψ)/(dx[SUP]2[/SUP]) + U(x)v = EΨ


∫ Ψ * Ψ dx = 1
I'm following Griffith's Modern Physics 2nd edition chapter 5.

I got to the part where we make ΨI(0) = ΨII(0) I get that

αCeα(0) = QAsin(Q(0)) - QBsin(Q(0)) => C = QA/α

But when I try to graph it, the region I distribution doesn't seem to equal the region II distribution at 0.

The book goes on on to insert C into an equation to solve for G (-αGe-α(L) for the other side of the well), but I don't understand why it does this.

-αGe-α(L) = (αC/Qs)sin(Q(L)) + C/cos(Q(L))Why does what happens on one side affect what happens on the other?
 
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The Floating Brain said:
Homework Statement:: There are two ledges with of U potential energy, and a cavern in between them of 0 potential energy. Such that

U(x) = { x <= 0, U, x > 0, x >= L, U }

Find the probability distribution for all 3 regions
Relevant Equations::2/2m)((d2Ψ)/(dx2) + U(x)v = EΨ∫ Ψ * Ψ dx = 1

I'm following Griffith's Modern Physics 2nd edition chapter 5.

I got to the part where we make ΨI(0) = ΨII(0) I get that

αCeα(0) = QAsin(Q(0)) - QBsin(Q(0)) => C = QA/α

But when I try to graph it, the region I distribution doesn't seem to equal the region II distribution at 0.
Your graph doesn't correspond to your work above. Back up a bit and tell us what you're using for ##\psi_I## and ##\psi_{II}##. And how did you get rid of ##B## to solve for ##C## from one equation?
 

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