An effect on atomic line spectra that occurs when the atoms are placed in a strong magnetic field. Spectral lines that give the anomalous Zeeman effect when the atoms are placed in a weaker magnetic field have a splitting pattern in a very strong magnetic field. The Paschen-Back effect is named after the German physicists Louis Carl Heinrich Friedrich Paschen (1865–1947) and Ernest E. A. Back (1881–1959), who discovered it in 1912. In the quantum theory of atoms the Paschen-Back effect is explained by the fact that the energies of precession of the electron's orbital angular momentum l and the spin angular momentum s about the direction of the magnetic field H are greater than the energies of coupling between l and s. In the Paschen-Back effect the orbital magnetic moment and the spin magnetic moment precess independently about the direction of H.
Subjects: Chemistry — Physics.