Otto Hahn (1879 – 1968) was the first President of the Max Planck Society, which was founded in 1948 from the ruins of the Kaiser Wilhelm Society and whose principal site was in Berlin-Dahlem. Otto Hahn conducted research there from 1913 to 1944 at the Kaiser Wilhelm Institute for Chemistry and was a regular visitor to Harnack House during that period. The lecture theatre was named after Otto Hahn in his memory after the renovation in 2014.
A chemist by background, Otto Hahn was appointed head of department at the Kaiser Wilhelm Institute (KWI) for Chemistry in Dahlem in 1913, which he later led as Director from 1928. Hahn conducted research there on radiochemistry, which was a new scientific field in the early 20th century and fostered cooperation between chemists and physicists. From 1907 onwards, Hahn began working closely with Lise Meitner, initially at the University of Berlin and later at the KWI for Chemistry. The young scientist was the second woman to obtain a doctorate in physics from the University of Vienna and had come to Berlin to seek fresh impetus under Max Planck. She was head of the radiophysics department at the KWI from 1918.
Otto Hahn frequently visited Harnack House during his time at the KWI. He gave several talks on his specialist field of radiochemistry in the lecture theatre. He also visited the venue in a private capacity as a regular guest at the club.
Otto Hahn and Fritz Straßmann discovered nuclear fission in Berlin-Dahlem in 1938. He shared his observations in correspondence with Lise Meitner who had been forced to emigrate from Germany several months earlier. She shared her views on the discovery and, together with her nephew Otto Robert Frisch, provided the physical explanation for Hahn’s experimental results. In 1945, Otto Hahn was awarded the 1944 Nobel Prize for his discovery of nuclear fission but was not able to accept it until 1946 after the end of the Second World War.
The Second World War dramatically highlighted the importance of Hahn’s discovery. The dropping of the first nuclear bombs on Hiroshima and Nagasaki in August 1945 documented the destructive power of nuclear fission. Hahn was deeply affected when he received the news in a British prisoner-of-war camp.
After the Second World War, Otto Hahn campaigned for the peaceful use of nuclear power. He instigated the Mainau Declaration (1955) and the Göttingen Manifesto (1957). Both public appeals called upon politicians and society to only deploy nuclear power for peaceful purposes. His new position as President of the Max Planck Society, founded in 1948 as the successor organization to the Kaiser Wilhelm Society, lent great weight to Otto Hahn’s words.
As President of the MPG, Hahn also endeavoured to achieve reconciliation with Israel. He led a delegation to the Weizmann Institute for Science in 1959 to establish scientific contacts. Remarking on the conduct of Germans during the Third Reich in a letter in 1949, Albert Einstein described Hahn as “one of the few to remain upstanding and to do their best during those dreadful years”. sk