= Zeeman effect
{c}
{wiki}
Split in the <spectral line> when a <magnetic field> is applied.
Non-anomalous: number of splits matches predictions of the <Schrödinger equation> about the number of possible states with a given angular momentum. TODO does it make numerical predictions?
<anomalous Zeeman effect>[Anomalous]: evidence of <spin (physics)>.
http://www.pas.rochester.edu/~blackman/ast104/zeeman-split.html contains the hello world that everyone should know: 2p splits into 3 energy levels, so you see 3 spectral lines from 1s to 2p rather than just one.
p splits into 3, d into 5, f into 7 and so on, i.e. one for each possible <azimuthal quantum number>.
It also mentions that polarization effects become visible from this: each line is polarized in a different way. TODO more details as in an experiment to observe this.
Well explained at: <video Quantum Mechanics 7a - Angular Momentum I by ViaScience (2013)>.
\Video[https://www.youtube.com/watch?v=ZmObNFAqkBE]
{title=Experimental physics - IV: 22 - Zeeman effect by Lehrportal Uni Gottingen (2020)}
{description=
This one is decent. Uses a <cadmium> lamp and an <etalon> on an <optical table>. They see a more or less clear 3-split in a circular <interference pattern>,
They filter out all but the transition of interest.
* https://youtu.be/ZmObNFAqkBE?t=165 passes the lines through a <polarizer>, which shows how orbital angular momentum is carried by <photon polarization>
* https://youtu.be/ZmObNFAqkBE?t=370 says they are looking at 1D2 to 1P1 changes.
}
\Video[https://www.youtube.com/watch?v=OzkcB1lkgGU]
{title=Zeeman Effect - Control light with magnetic fields by <Applied Science (YouTube channel)> (2018)}
{description=Does not appear to achieve a crystal clear split unfortunately.}