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donquixote17

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## Homework Statement

I need to solve the Schroedinger equation (Using DSolve in Mathematica) for a potential that is infinite below z=0 and V=mgz for positive z.

## Homework Equations

TISE:

[itex] \psi \text{''}[z]+\frac{2 m}{\hbar }(\text{En}-V[z])\psi [z]==0 [/itex]

## The Attempt at a Solution

First I defined the potential as

[itex]V[z]=\text{Piecewise}[\{\{\infty ,z<0\},\{m g z,z\geq 0\}\}];[/itex]

Then I told Mathematica to solve the Diffeq

[itex]\text{DSolve}\left[\left\{\psi \text{''}[z]+\frac{2 m}{\hbar }(\text{En}-V[z])\psi [z]==0,\psi [0]==0,\psi [\infty ]==0\right\},\psi [z],z\right][/itex]

The error mathematica gave me was

InverseFunction::ifun: Inverse functions are being used. Values may be lost for multivalued inverses. >>

I'm not really sure how to get mathematica to give me the solution. I know I need 2 conditions besides the diffeq in order to solve. The only boundary condition that I know to use is that the wavefunction must be zero at z=0 since the potential is infinite there.

Any ideas on what second boundary condition I should use or any ideas on where I'm going wrong? Thanks

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