Photon absorption and probability of atomic electron transition

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Discussion Overview

The discussion revolves around the process of photon absorption by a hydrogen atom and the implications for atomic electron transitions as described by the Schrödinger equation. Participants explore the quantum mechanical treatment of this phenomenon, including the role of wavefunctions and the calculation of transition probabilities.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant questions the classical interpretation of photon absorption as a collision, suggesting it may be an oversimplification.
  • Another participant mentions that the Schrödinger equation can be modified to account for the interaction with the photon, though this introduces time-dependent potentials.
  • There is a proposal to compute the probability of photon absorption and electron transitions using the wavefunction derived from the modified Schrödinger equation.
  • A later reply indicates that the probability amplitude for transitions depends on the overlap of the wavefunctions of the involved orbitals, referencing Fermi's Golden Rule.
  • One participant emphasizes the complexity of the calculations and suggests familiarity with quantum mechanics and quantum optics is necessary for a deeper understanding.
  • Another participant notes that the electron-photon interaction term is typically omitted initially in the Schrödinger equation and then included perturbatively, often using the dipole approximation.

Areas of Agreement / Disagreement

Participants express varying levels of understanding and approaches to the problem, with no consensus on the best method to treat photon absorption and electron transitions. The discussion remains unresolved regarding the most accurate or preferred model for these processes.

Contextual Notes

Participants acknowledge the limitations of their current knowledge and the complexity of the mathematical treatment involved in photon absorption and atomic transitions. The discussion highlights the need for a solid foundation in quantum mechanics and related fields to fully engage with the topic.

Who May Find This Useful

Individuals interested in quantum mechanics, atomic physics, and the interaction of light with matter may find this discussion relevant, particularly those seeking to understand the nuances of photon absorption and electron transitions in atoms.

PhysicsAm55
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I have only taken one very intro quantum mechanics class and the furthest we got was solving the Schrödinger equation for the Coulumb potential of the hydrogen atom.
So we solved for the allowed energy levels and the wavefunction for the hydrogen atom. We also learned how using the wavefunction, the electron orbitals can be constructed as probability "clouds" around the nucleus.

Now the question I have is how does one deal with this hydrogen atom absorbing a photon in terms of the Schrödinger equation?

I was taught in modern physics that when an atom absorbs a photon, its energy is increased and the electron moves up to a higher energy level. But is it even correct to say that the atom absorbs the photon? I know some sources state and my professor stated a few times that the photon 'bumps' the electron up to a higher energy level but I assumed that this was a simplified and wrong way to look at the situation since it is treated like a classical collision (the photon actually colliding with the electron). I just wanted to mention this and ask here if I was right to dismiss this classical picture of the situation?

To try to answer my own question: I guess when the photon comes close enough to the hydrogen atom you must resolve the Schrödinger equation with a different potential energy function. This is different from anything I have learned because the potential would now depend on time so I would not know where to begin here, but let's say you solved the Schrödinger equation and find the wavefunction. Do you use this wavefunction to compute the probability of the photon being absorbed? and for the electron making an atomic transition? If so how would you go about this? Lastly how would you find the probability of Auger electrons after the excited electron returns to its ground state.

I thank you for your time and eagerly await your response!
 
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Does anyone have any recommended resources that could answer my questions?
 
There is no simple answer to your question.
Yes, it is possible to calculate all those things, and yes the probability amplitude for a transition depends on the overlap of the wavefunctions of the orbitals involved in the transitions.
Look up e.g. Fermi's Golden Rule.

However, the details are quite complicated and require both a working knowledge of "standard" QM at the level of e.g. Sakurai, and some knowledge about quantum optics.
The best reference I can think of is Cohen-Tannoudji's book on atom-photon interactions.
 
The electron-photon interaction term (always present in nature) is first omitted in the Schroedinger equation. This gives the atomic wave functions (non perturbed). Then the interaction term is taken into account perturbatively. Often one uses the so called dipole approximation, so the matrix elements contain simply r instead of exact interaction potential.
 

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