Landé, Alfred (1888–1975)

German-born US quantum physicist. In 1923 he published a formula expressing a factor, now known as the Landé splitting factor, for all multiplicities as a function of the quantum numbers of the stationary state of the atom.

Landé was born in Elberfeld and studied at Marburg, Göttingen, and Munich. From 1922 he was on the staff at Tübingen, the main centre of atomic spectroscopy in Germany. He emigrated to the USA 1931, because of the rise of the Nazi regime, to settle in Columbus, Ohio, as professor of theoretical physics at Ohio State University.

In collaboration with German physicist Max Born, Landé published a paper 1918 on their conclusion that Danish physicist Niels Bohr's model of coplanar electronic orbits must be wrong, and that they must be inclined to each other. Later Landé visited Bohr in Copenhagen to discuss the Zeeman effect (the splitting of spectral lines in a magnetic field), which pointed him towards the discovery of the Landé splitting factor. This is the ratio of an elementary magnetic moment to its causative angular momentum when the angular momentum is measured in quantized units.