Irving Langmuir (31.01.1881-16.08.1957) was an American physicist and chemist and a member of the National Academy of Sciences. He was born in New York. He graduated from Columbia University (1903). In 1906 he received his doctorate at the University of Göttingen. In 1909 — 57 he worked at the laboratory of the General Electric Company (deputy director in 1929 —50). His work in physics concerned the study of discharges in gases, plasma physics, electronics and atomic physics, in particular chemical reactions at high temperatures and low pressures, thermal effects in gases, atomic structure, thermionic emission and chemical forces in solids, liquids and surface films. Many of these studies led to the development of a number of technologies. He made an important contribution to the study of processes in electron tubes, establishing in 1913 the law for the current density of thermionic emission (the Langmuir law). His research on the phenomena of electric discharges in gases and on thermionic emission was used in the design of various electronic devices. He built a gas-tube rectifier. In 1911 he obtained atomic hydrogen and proposed a process for welding metals in a hydrogen flame (the Langmuir hydrogen torch). In 1913 he designed a molecular manometer and in 1916 the first mercury-vapour condensation vacuum pump. He developed (1912) a theory of thermal conductivity. In 1919 he worked out a model of the atom (the Langmuir model of the atom). In 1929, together with L. Tonks, he introduced the concept of the plasma and of plasma oscillations (Langmuir oscillations). He is known for the Langmuir — Saha equation (1924). He constructed (1919) a theory of chemical valence (the Lewis—Langmuir theory). In 1916 he gave the equation of the isotherm of monomolecular adsorption.
Nobel Prize in Chemistry (1932). A member of a number of academies of sciences and scientific societies. The D. Hughes (1918), B. Rumford (1920), J. Gibbs (1930), B. Franklin (1934) and M. Faraday (1938, 1943) medals and others.