Isidor Isaac Rabi
Born: 29 July 1898, Rymanow, Austria-Hungary (now Poland)
Died: 11 January 1988, New York, NY, USA
Affiliation at the time of the award: Columbia University, New York, NY, USA
Prize motivation: "for his resonance method for recording the magnetic properties of atomic nuclei"
Field: nuclear physics
Prize share: 1/1
Protons and neutrons in nuclei act like small, rotating magnets. Atoms and molecules therefore align in a magnetic field. In 1938, Isaac Isidor Rabi passed a beam of molecules through a magnetic field. When the beam was exposed to radio waves, the direction of rotation could be changed, but only in certain stages, in accordance with quantum mechanics. When the atoms returned to their original positions, they emitted electromagnetic radiation with uniquely characteristic frequencies.