Meitner, Lise (lēˈzə mĪtˈnər) [key], 1878–1968, Austrian-Swedish physicist and mathematician. She was professor at the Univ. of Berlin (1926–33). A refugee from Germany after 1938, she became associated with the Univ. of Stockholm and with the Nobel Institute at Stockholm. In 1917, working with Otto Hahn, she isolated the most stable isotope of the element protactinium; she also investigated the disintegration products of radium, thorium, and actinium and the behavior of beta rays. In 1938 she participated in experimental research in bombarding the uranium nucleus with slow-speed neutrons. Meitner interpreted the results as a fission of the nucleus and calculated that vast amounts of energy were liberated. Her conclusion contributed to the development of the atomic bomb. In 1949, she became a Swedish citizen. The element with the atomic number 109 is named meitnerium in her honor.
See biography by R. L. Sime (1996); P. Rife, Lise Meitner and the Dawn of the Nuclear Age (1997).