Calculating Probabilities and Expectation Values for Hydrogen Atom Wave Function

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SUMMARY

The discussion focuses on calculating probabilities and expectation values for a hydrogen atom's wave function represented as a superposition of energy eigenfunctions. The wave function at time t=0 is given by Ψ(r, t=0) = (1/√14) * [2ψ100(r) - 3ψ200(r) + ψ322(r)]. Participants address the probability of finding the system in various states and the expectation values of energy, L², and Lz operators. Key insights include the necessity of integrating over the entire space and the realization that orthogonal eigenfunctions yield zero when integrated together.

PREREQUISITES
  • Quantum mechanics fundamentals, specifically wave functions and energy eigenstates.
  • Understanding of hydrogen atom wave functions, including ψ100, ψ200, and ψ322.
  • Knowledge of integration techniques in spherical coordinates.
  • Familiarity with operators in quantum mechanics, particularly L² and Lz.
NEXT STEPS
  • Study the properties of orthogonal functions in quantum mechanics.
  • Learn about the normalization of wave functions in quantum systems.
  • Explore the calculation of expectation values for quantum operators.
  • Investigate the use of spherical coordinates in quantum mechanical integrals.
USEFUL FOR

Students and professionals in quantum mechanics, physicists working with atomic systems, and anyone interested in the mathematical foundations of wave functions and their applications in quantum theory.

Shafikae
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Consider a hydrogen atom whose wave function is at t=0 is the following superposition of energy eigenfunctions \psinlm(r)
\Psi(r, t=0) = \frac{1}{\sqrt{14}} *[2\psi100(r) -3\psi200(r) +\psi322(r)

What is the probability of finding the system in the ground state (100? in the state (200)? in the state (322)? In another energy eigenstate?
For this part i found each eigen state and put it into an integral. Should there be limits of integration for r? If so, from where to where? I did the integration for (100) and (200) but for (322) i got something crazy.

What is the expectation value of the energy: of the operator L2, of the operator Lz
I have no clue what to do here.
 
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You integrate over all of space. But to give a hint, if you recall (or read up on) the properties of eigenfunctions, you'll realize you don't need to explicitly do the integration here.
 
I know that if the subscripts are different then the int of
\psi* \psi =0
I got something crazy for
\psi322

but I was able to get the other 2 states. Am I suppose to integrate in terms of r from 0 to \infty ?
Thank you.
 

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