 Zeeman effect

The Zeeman effect is a phenomenon in physics observed when the spectral lines of atoms are split into multiple components in the presence of a magnetic field. This splitting results from the interaction between the magnetic field and the magnetic dipole moment associated with the angular momentum of electrons within an atom. When an atom is placed in a magnetic field, the degeneracy of energy levels associated with electronic states is lifted due to the different orientations of the magnetic moments relative to the field direction.

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: evidence of spin.

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)".