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Q & A: magnetism in hydrogen atom

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Most recent answer: 07/28/2013
Q:
just a question about electron proton interaction : why in atom model for hydrogen only the coloumb law is taken in account (schrodinger eq. in radial coordinates with legendre solution ) where is the magnetic field effect of interaction between a negative charge and positive charge , is the electron fixed.
- pg (age 57)
italy
A:

Actually, there is an interaction in hydrogen between the proton spin and the electron spin. The energy difference between the spin-parallel and spin anti-parallel states is quite small compared to the main electrostatic binding energy. It is, however, measurable. The effect splits the electron paramagnetic resonance lines for any molecules containing hydrogen, something I measured routinely as a youth.

You seem to be thinking of another effect, involving the orbital motion. In the rest frame of the atom, the proton isn't going anywhere, so its only magnetic field comes from the spin. As for the electron. it's in a spherically symmetric state with no tangential components of its velocity. That leads to the absence of any spin-orbit effects. (see In big atoms with large tangential velocity components for some of the electrons, spin-orbit effects do indeed have to be considered.

Mike W.


(published on 07/28/2013)

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