Nikolai Nikolaevich Semenov (April 3 (15), 1896, Saratov – September 25, 1986, Moscow) was a Soviet physicochemist, one of the founders of chemical physics.

Academician of the Academy of Sciences of the USSR (1932; corresponding member since 1929), the only Soviet winner of the Nobel Prize in Chemistry (he received it in 1956 together with Cyril Hinshelwood).

Chairman of the Board of All-Union Society “Znanie” (1960-1963).

Nikolai Semenov was born in Saratov, his parents were Nikolai Alexandrovich and Elena Alexandrovna Semenovs. In 1913, Nikolai graduated from Samara Real School with a gold plaque.

His physics teacher in the seventh grade of the school (1912-1913) was Vladimir Ivanovich Karmilov, a graduate of the physics and mathematics faculty of Kazan University, who supported the young Semenov’s desire to devote his life to science and maintained a warm friendship with him in later years. In July 1913 Semenov enrolled in the Mathematics Department of the Physics and Mathematics Department of Petrograd University.

His father, a former officer, hoped that his son would pursue a military career, so entry into the university caused a family rift and estrangement between father and son that lasted several years. From his second year in the university, Semenov started his study of science under the supervision of Alexey Ioffe, where he performed several studies on the ionization of atoms and molecules by electron impact in the gas discharges. He graduated from the university in 1917 with a first-degree diploma and was left at the university as a professor’s scholar (the analog of a post-graduate course).

In the spring of 1918, Semenov went to his parents in Samara for a vacation, where he was caught by the mutiny of the Czechoslovak Corps. In June 1918, power in Samara was taken over by the Social Revolutionary Komuch (Committee of Members of the Constituent Assembly). In July Semenov volunteered to the White Guard People’s Army, served as a horse-driver in an artillery battery. After serving for 3 weeks, Semyonov received word of his father’s serious illness (who soon died) and obtained a leave to return home. In Samara he “arranged a transfer to the newly forming Ufa Battery,” but on the way to his new duty station he deserted and went to Tomsk, which was the nearest university town available to him under war conditions.

For about two years, from September 1918 to March 1920 (with a break), the scientist worked at Tomsk University and the Tomsk Institute of Technology. In September 1919 Semenov was mobilized in the Kolchakovsk army and got into a Tomsk artillery division first, and a month later, thanks to the petition of university professors, he was transferred to radiobattalion and seconded to the Institute of Technology, where he continued his scientific research. In December 1919 Tomsk was occupied by the Red Army, radio battalion was transferred to it, and by the order of the commandant of Tomsk Semenov was dismissed from service and continued his scientific and teaching work.

In May 1920 Semenov returned to Petrograd, invited by A. F. Ioffe, who was involved in creation of the Physico-Technical Institute of Roentgenology, and headed the laboratory of electronic phenomena, and in 1922 he was appointed deputy director of the Physico-Technical Institute.

In 1922 Semenov, in co-authorship with Peter Kapitsa, proposed a method for measuring the magnetic moment of the atom in an inhomogeneous magnetic field. This method was successfully developed the same year by Otto Stern and Walter Gerlach (see Stern-Gerlach experiment).

Since 1928 Semenov was a part-time professor at the Leningrad Polytechnic Institute. In 1927 N. N. Semenov became the head of the Chemical Physics Department of PTI, on whose basis in 1931 he established the Institute of Chemical Physics of the USSR Academy of Sciences (currently ICP RAS), whose permanent director he was until the end of his life. A few years after its foundation, the Institute moved to Moscow.

In 1929 N. N. Semenov was elected a corresponding member and in 1932 a full member of the USSR Academy of Sciences.

In 1934 he published his monograph “Chemical Kinetics and Chain Reactions” where he substantiated the existence of the chain or branched chain reaction mechanism, which is responsible for many chemical processes, including polymerization reactions.

With the beginning of the Great Patriotic War in 1941, Semenov was evacuated to Kazan, where he studied problems of combustion and explosion. In 1943, together with the Institute of Chemical Physics, he returned from evacuation to Moscow.

In 1944, when the Physics Department of Moscow State University just returned from evacuation, Semenov started to teach at MSU. He was more than coolly accepted at the prestigious university, a situation that was cited by A. F. Ioffe as a negative example. F. Ioffe in a letter of four academicians to V. M. Molotov in the summer of 1944. In 1944, the scientist organized the Department of Chemical Kinetics at the Faculty of Chemistry of Moscow University, which he headed for more than 40 years.

Together with P.L. Kapitsa, he was one of the founders of the Moscow Institute of Physics and Technology in 1946, and he was the founder and scientific director of the department of molecular and chemical physics at this Institute.

In the 1940s and 50s, he participated in the Soviet atomic project.

In 1947 he joined the CPSU, was a candidate member of the CPSU Central Committee from 1961 to 1966, was three times elected deputy to the Supreme Soviet of the USSR.

In 1958 Semenov was the XII Mendeleev reader. He was Academician-Secretary of the Department of Chemical Sciences of the USSR Academy of Sciences (1957-1971), Vice-President of the USSR Academy of Sciences from July 4, 1963 to May 28, 1971.

In 1960-1963 he was the chairman of the board of the All-Union Educational Society “Znanie”, he was succeeded in this position by V.A. Kirillin.

Since 1981 he has been the editor-in-chief of the journal Chemical Physics. Semenov actively participated in the movement of scientists against the threat of nuclear war (Pugwash movement).

The Semenov scientific school includes a number of major physicists and chemists: Ya. B. Zeldovich, V. N. Kondratyev, Yu. B. Khariton, K. I. Shchelkin, N. M. Emanuel, D. A. Frank-Kamenetsky, and others.