Calculating transition rate between nljm resolved states

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SUMMARY

This discussion focuses on calculating transition rates between nljm states in hydrogen-like atoms, specifically addressing the complexities introduced by spin angular momentum. The dipole transition rate formula is provided, which includes a radial integral and an angular part involving spherical harmonics. The participant successfully applies Clebsch-Gordan coefficients for certain cases but struggles with integrating spin angular momentum, leading to discrepancies in results. The need for resources on angular momentum addition and degeneracy in quantum mechanics is emphasized.

PREREQUISITES
  • Understanding of quantum mechanics principles, particularly angular momentum.
  • Familiarity with dipole transition rates and their mathematical formulations.
  • Knowledge of Clebsch-Gordan coefficients and their application in quantum states.
  • Experience with spherical harmonics and their role in quantum mechanics.
NEXT STEPS
  • Research the role of spin in quantum mechanics and its effect on transition rates.
  • Study the addition of angular momentum in quantum systems, focusing on half-integer values.
  • Explore resources on calculating matrix elements involving spin and angular momentum.
  • Investigate the implications of degeneracy in quantum state transitions.
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Quantum physicists, graduate students in physics, and researchers working on atomic transition rates and angular momentum in quantum systems.

Khashishi
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I know how to calculate transition rates between nl resolved states in a hydrogen-like atom, but I don't know how to calculate transition rates between nljm states.

I know that dipole transition rate is
[itex]\frac{32}{3}\frac{\pi^3 \alpha c}{\lambda^3}\left<\psi_1|\mathbf{d}|\psi_2\right>[/itex]
The matrix elements on the right can be separated into a radial integral and an angular part. The radial part is
[itex]\int R_{nl} R_{n'l'} r^3\,\mathrm{d}r[/itex]
If we pretend that spin doesn't exit, the angular part goes something like
[itex]\iint {Y_l^m}^{*} Y_1^{0,\pm 1} Y_{l'}^{m'} \sin(\theta) \,d\theta\,d\phi[/itex]
I can solve this using Clebsch Gordan coefficients, and it seems to give the right answer. But, I have no idea what to do when I add in spin angular momentum. It seems this integral doesn't make sense if I replace l with with 1/2 integer j.

I tried some various things, and I ended up with something that gave the right answer in some cases but not in others. I'm always off by some multiple of some rational. I know it has to do with degeneracy and angular momentum addition, but I can't figure it out. Any resources?
 
Physics news on Phys.org
When including spin, ##j## replaces ##l## in the angular part.
 

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