hyperfinestruktur
Hyperfinestruktur refers to a subtle splitting of spectral lines in atoms that arises from the interaction between the magnetic dipole moment of the nucleus and the magnetic field generated by the orbital motion of electrons. This effect is a refinement of the finer structure, which is caused by the interaction between the electron's spin magnetic dipole moment and the magnetic field produced by its own orbital motion. The hyperfinestruktur is therefore a manifestation of magnetic interactions within the atom, involving both electronic and nuclear magnetic moments.
The magnitude of the hyperfinestruktur splitting is typically much smaller than that of the finer structure.