Fine structure

This is a section about Fine structure!

Fine structure is a very important subject about which there is a lot to say.

For example, this sentence. And then another one.

This is a section about Fine structure!

Fine structure is a very important subject about which there is a lot to say.

For example, this sentence. And then another one.

Split in energy levels due to interaction between electron up or down spin and the electron orbitals.

Numerically explained by the Dirac equation when solving it for the hydrogen atom, and it is one of the main triumphs of the theory.