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Stern, Otto

magnetic beam spin molecular

(1888–1969) German–US physicist: showed that magnetic fields of atoms are quantized.

Otto Stern, the son of a grain-merchant, completed his doctorate in Breslau in 1912. He travelled and attended lectures by and and became a post-doctoral associate and friend of in Zürich. Following military service during the First World War he worked with in Frankfurt on statistical mechanics.

In 1920 Stern and W Gerlach (1889–1979) collaborated in a historic experiment. A molecular beam of silver atoms (produced by heating the metal in a vacuum) was used to investigate whether space quantization (proposed by Sommerfeld) occurs or not. A silver atom should possess a magnetic moment (spin) and when placed in a non-uniform magnetic field should be found in two (spin-up or spin-down) configurations, so that the beam would be split into two distinct beams by such a field. Such quantum mechanical space-quantization was proved by the Stern–Gerlach experiment, and Stern was awarded the 1943 Nobel Prize for physics.

Stern took a professorship at Hamburg and set up a large molecular-beam laboratory, collaborating with and P Ehrenfest (1880–1933). Stern determined the magnetic moment of the proton and found it to have two to three times the value predicted by . In 1933 Stern moved to Carnegie Institute of Technology, Pittsburgh, but the momentum of the Hamburg laboratory was not regained and he retired early. He enjoyed luxury, good food and the cinema, and it was in a cinema that he died of a heart attack at 81.

[back] Stern, Madeleine Bettina (1912–) - U.S. Women’s History

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