Otto Hahn

Otto HahnOtto Hahn (1879-1968)
The Nobel Prize in Chemistry 1944

Otto Hahn was born on March 8, 1879, at Frankfurt-on-Main. He attended the secondary high school there until he matriculated.

From 1897, Hahn studied chemistry at Marburg and Munich, taking his doctorate examination in 1901 at Marburg and submitting to Professor Theodor Zincke a thesis on organic chemistry.

He obtained a post as an assistant at the Chemical Institute at Marburg, staying there for two years, after which he worked under Sir William Ramsay at University College, London, from the autumn of 1904 until the following summer. His work here was rewarded by the discovery of a new radioactive substance, radiothorium, while working on the preparation of pure radium salts.

From autumn 1905 to the summer of the following year Hahn was at the Physical Institute of McGill University, Montreal (Canada) working under Professor Ernest Rutherford. Here he discovered radioactinium and conducted investigations with Rutherford on alpha-rays of radiothorium and radioactinium.

On his return to Europe Hahn moved to Berlin, to the Chemical Institute (Emil Fischer) of the University and there he qualified as a university lecturer in the spring of 1907, which year also saw his discovery of mesothorium.

At the end of 1907, a 30 year collaboration began with Dr. Lise Meitner’s arrival from Vienna. Their joint work embraced investigations on beta-rays, their absorbability, magnetic spectra, among others; the use of radioactive recoil, which had been discovered shortly before by Hahn, to obtain new radioactive transformation products.

Between 1914 and 1918 Hahn’s work was interrupted by his service in the First World War, but he resumed his research with Professor Meitner in 1918, and discovered protactinium, the long-lived mother substance of the actinium series. Hahn’s own particular sphere was chemistry and he further discovered uranium Z, the first case of a nuclear isomerism of radioactive kinds of atoms. Using radioactive methods he investigated the absorption and precipitation of the smallest quantities of substances, normal and abnormal formation of crystals, etc. Hahn used the emanation method to test substances superficially rich or poor, and he elaborated the strontium method to determine the age of geological periods.

Following the discovery of artificial radioactivity by M and Mme. Joliot-Curie and the use of neutrons by Fermi for atomic nuclear processes, Hahn again collaborated with Professor Meitner and later with Dr. Strassmann on the processes of irradiating uranium and thorium with neutrons.

Hahn and Prof. Meitner also worked together on the discovery of an artificially active uranium isotope, which represents the basic substance of the elements neptunium and plutonium, first revealed later in America.

His most spectacular discovery came at the end of 1938. While working jointly with Dr. Fritz Strassmann, Hahn discovered the fission of uranium and thorium in medium heavy atomic nuclei. His first work on these subjects appeared on January 6 and February 10, 1939, in Naturwissenschaften. Hahn continued investigations on the proof and separation of many elements and kinds of atoms which arise through fission until 1944.

In 1913 Hahn married Edith, née Junghans and they had one son, Hanno, born in 1922, who was accidentally killed in 1960.

Otto Hahn died on July 28, 1968.