Ilya Prigogine (Ilya Romanovich) ( born 25.01.1917) — Belgian physicist and physical chemist, one of the founders of non-equilibrium thermodynamics, member of the Belgian Academy of Sciences (1953), its president in 1969. Born in Moscow. Graduated from the University of Brussels (1942), where he works (from 1947 — professor). From 1962 — also director of the International Institute of Physics and Chemistry (Solvay, Belgium), from 1967 — of the Center for Statistical Mechanics and Thermodynamics of the University of Texas (USA).
His work was in the fields of non-equilibrium thermodynamics and physical chemistry. He made a significant contribution to the phenomenological theory of irreversible processes and to the thermodynamics of nonlinear irreversible processes. He introduced (1947) the concepts of entropy production and entropy flux, gave the so-called local formulation of the second law of thermodynamics, and proposed the principle of local equilibrium. He showed (1947) that in a stationary state at fixed external parameters the rate of entropy production in a thermodynamic system is a minimum (the Prigogine theorem) and that the entropy production for irreversible processes in an open system tends to a minimum (the Prigogine criterion). He carried out the first work on the statistical thermodynamics of irreversible processes. He substantiated (1959—60) the thermodynamic relations for gases in a non-equilibrium state, and showed that the macroscopic expression for the intensity of a source (and also the Onsager reciprocal relations) can be obtained from the basic equations of kinetic theory. For his work on the thermodynamics of irreversible processes and its application in chemistry and biology he was awarded the Nobel Prize in Chemistry in 1977.
Member of a number of academies of sciences and scientific societies, in particular foreign member of the USSR Academy of Sciences (1982). E. Solvay Prize (1965), S. Arrhenius Gold Medal (1969), B. Rumford Medal (1976) and others.