Karl Herzfeld

Karl Herzfeld
Karl Herzfeld
	Herzfeld (right) in 1938
Born	Karl Ferdinand Herzfeld; February 24, 1892; Vienna, Austria-Hungary
Died	June 3, 1978 (aged 86); Washington DC, US
Education	Schottengymnasium
Alma mater	University of Vienna (Dr. phil.)
Spouse	Regina Flannery (m. 1938)
	Scientific career
Fields	Physics; chemistry;
Institutions	University of Munich ; (1919–26); Johns Hopkins University (1926–36); Catholic University of America (1936–69);
Doctoral advisor	Friedrich Hasenöhrl
Doctoral students	Walter Heitler (1926); John A. Wheeler (1933); Virginia Griffing (1947);

Karl Ferdinand Herzfeld (February 24, 1892 – June 3, 1978) was an Austrian–American physicist and chemist. He worked on condensed matter physics, fluid dynamics, and statistical mechanics. In 1927, he was the first to quantify when a substance is a metal or an insulator. The Goldhammer–Herzfeld criterion to classify metalloids is named after him. With Frank O. Rice, he studied the rate equations of the pyrolysis of acetaldehyde in 1934. Their model is known as the Rice–Herzfeld mechanism.

Herzfeld also wrote on philosophy and theology. He was married to anthropologist Regina Flannery.