Van Vleck, John H.

Van Vleck, John H. (Hasbrouck) (1899–1980) physicist; born in Middletown, Conn. Educated entirely in the U.S.A., he taught at Harvard (1922–23) and the University of Minnesota (1923–28), where, in 1926, he expanded English physicist Paul Dirac's quantum mechanics to explain the electric and magnetic properties of atoms. His classical treatise, The Theory of Electric and Magnetic Susceptibilities (1932), published while he was teaching at the University of Wisconsin (1928–34), earned Van Vleck the title "father of modern magnetism." He promoted the union of physics and chemistry, applying his discoveries to chemical bonding in crystals. Returning to Harvard (1934–69), he used his theory in studies of nuclear magnetic resonance and in the development of computer memory systems. He shared the 1977 Nobel Prize in physics (with Philip Anderson and Nevill Mott) for his pioneering research. His colleagues knew him as a patient, gentle man whose personal interests included collecting detailed information of U.S. and European railroad timetables.