Elise Lise Meitner ( ; ; 7 November 1878 – 27 October 1968) was an Austrian and Swedish nuclear physicist who was instrumental in the discovery of nuclear fission.
After completing her doctoral research in 1906, Meitner became the second woman to earn a doctorate in physics from the University of Vienna. She spent much of her scientific career in Berlin, where she was a physics professor and a department head at the Kaiser Wilhelm Institute for Chemistry. She was the first woman to become a full professor of physics in Germany. She lost her positions in 1935 because of the anti-Jewish Nuremberg Laws of Nazi Germany, as well as her citizenship after the 1938 annexation of Austria by Germany. On 13–14 July 1938, she fled to the Netherlands with the help of Dirk Coster. She lived in Stockholm for many years, ultimately becoming a Swedish citizen in 1949, while insisting on keeping her Austrian citizenship, but relocated to Britain in the 1950s to be with family members.
In mid-1938, chemists Otto Hahn and Fritz Strassmann at the Kaiser Wilhelm Institute for Chemistry demonstrated that isotopes of barium could be formed by neutron bombardment of uranium. Meitner was informed of their findings by Hahn, and in late December, with her nephew, fellow physicist Otto Robert Frisch, she worked out the physics of this process by correctly interpreting Hahn and Strassmann's experimental data. On 13 January 1939, Frisch replicated the process Hahn and Strassmann had observed. In Meitner and Frisch's report in the February 1939 issue of Nature, they gave the process the name "fission". The discovery of nuclear fission led to the development of nuclear reactors and atomic bombs during World War II.
Meitner did not share the 1944 Nobel Prize in Chemistry for nuclear fission, which was awarded to her long-time collaborator Otto Hahn. Several scientists and journalists have called her exclusion "unjust". According to the Nobel Prize archive, she was nominated 19 times for the Nobel Prize in Chemistry between 1924 and 1948, and 30 times for the Nobel Prize in Physics between 1937 and 1967. Despite not having been awarded the Nobel Prize, Meitner was invited to attend the Lindau Nobel Laureate Meeting in 1962. She received many other honours, including the posthumous naming of element 109 meitnerium in 1997.
Early years Elise Meitner was born in November 1878 into a Jewish upper-middle-class family at the family home in 27 Kaiser Josefstraße in the Leopoldstadt district of Vienna. She was the third of eight children of chess master Philipp Meitner and his wife Hedwig. The birth register of Vienna's Jewish community lists her as being born on 17 November 1878, but all other documents list her date of birth as 7 November, which is what she used.
Her father was one of the first Jewish lawyers admitted to practice in Austria. She had two older siblings, Gisela and Auguste (Gusti), and four younger: Moriz (Fritz), Carola (Lola), Frida and Walter; all ultimately pursued an advanced education. Her father was a freethinker, and she was brought up as such.
As an adult, she converted to Christianity, following Lutheranism, and was baptised in 1908; her sisters Gisela and Lola converted to Catholicism that same year. She also adopted the shortened name "Lise".
Education Meitner's interest in science began when she was eight, when she kept a notebook of her scientific research under her pillow. She was drawn to mathematics and science, and studied the colours of an oil slick, thin films, and reflected light. The only career available to women was teaching, so she attended a high school for girls where she trained as a French teacher. As well as French, her education included bookkeeping, arithmetic, history, geography, science and gymnastics. She completed high school in 1892.
Women were not allowed to attend public institutions of higher education in Vienna until 1897, but when this restriction was lifted, the requirement for a gymnasium education was waived and women only needed to pass the , the secondary school leaving qualification required for university entrance. Her sister Gisela passed the and entered medical school in 1900. Meitner began taking private lessons with two other young women in 1899, cramming the missing years of secondary education into two. Physics was taught by Arthur Szarvasy.
In July 1901, they sat an external examination at the Akademisches Gymnasium. Four out of the fourteen women passed, including Meitner and Henriette Boltzmann, the daughter of physicist Ludwig Boltzmann.
Research, work and academia University of Vienna
Meitner entered the University of Vienna in October 1901. She was particularly inspired by Ludwig Boltzmann and often spoke with enthusiasm about his lectures. Her dissertation was supervised by Franz Exner and his assistant Hans Benndorf. Her thesis was submitted on 20 November 1905 and approved on 28 November. She passed an oral exam from Exner and Boltzmann on 19 December, and was awarded her doctorate on 1 February 1906. She became the second woman to earn a doctoral degree in physics at the University of Vienna, after Olga Steindler who had received her degree in 1903; the third was Selma Freud, who worked in the same laboratory as Meitner, and received hers in 1906. Meitner's thesis was published as () on 22 February 1906.
Paul Ehrenfest asked her to investigate an article on optics by Lord Rayleigh detailing an experiment that produced results Rayleigh had been unable to explain. She was able to explain the results, and also made predictions based on her explanation, which she then verified experimentally, demonstrating her ability to carry out independent and unsupervised research. She published the results in her report on "Some Conclusions Derived from the Fresnel Reflection Formula". In 1906, while engaged in this research, Meitner was introduced by Stefan Meyer to radioactivity, then a very new field of study. She started with alpha particles. In her experiments with collimators and metal foil, she found that scattering in a beam of alpha particles increased with the mass of the metal atoms. She submitted her findings to the on 29 June 1907. This was one of the experiments that led Ernest Rutherford to predict the nuclear atom.
Friedrich Wilhelm University
Encouraged and backed by her father's financial support, Meitner entered the Friedrich Wilhelm University in Berlin, where the renowned physicist Max Planck taught. Planck invited her to his home, and allowed her to attend his lectures. This was an unusual gesture by Planck, who was on record as opposing the admission of women to universities in general, but apparently recognised Meitner as an exception. She became friends with Planck's twin daughters Emma and Grete, who were born in 1889, and shared Meitner's love of music.
Attending Planck's lectures did not take up all her time, and Meitner approached Heinrich Rubens, the head of the experimental physics institute, about doing some research. Rubens said that he would be happy for her to work in his laboratory. He also added that Otto Hahn at the chemistry institute was looking for a physicist to collaborate with. A few minutes later she was introduced to Hahn. He had studied radioactive substances under William Ramsay and Ernest Rutherford, and was already credited with the discovery of what were then thought to be several new radioactive elements. Hahn was the same age as Meitner, and she noted his informal and approachable manner. In Montreal, Hahn had become accustomed to collaboration with physicists—including at least one woman, Harriet Brooks.
The head of the chemistry institute, Emil Fischer, placed a former woodworking shop () at Hahn's disposal in the basement to use as a laboratory. Hahn equipped it with electroscopes to measure alpha and beta particles and gamma rays. It was not possible to conduct research in the wood shop, but Alfred Stock, the head of the inorganic chemistry department, let Hahn use a space in one of his two private laboratories. Like Meitner, Hahn was unpaid, and lived off an allowance from his father, although somewhat larger than hers. He completed his habilitation in early 1907, and became a . Most of the organic chemists at the chemistry institute did not regard Hahn's work—detecting minute traces of isotopes too small to see, weigh or smell through their radioactivity—as real chemistry. One department head remarked that "it is incredible what one gets to be a these days!" Lise Meitner helped discover the radioactive element protactinium.
The arrangement was difficult for Meitner at first. Women were not yet admitted to universities in the German state of the Kingdom of Prussia, which included Berlin. Meitner was allowed to work in the wood shop, which had its own external entrance, but she could not enter the rest of the institute, including Hahn's laboratory space upstairs. If she wanted to go to the toilet, she had to use one at the restaurant down the street. The following year, women were admitted to Prussian universities, and Fischer lifted the restrictions, and had women's toilets installed in the building. Not all the chemists were happy about this. The Institute of Physics was more accepting, and she became friends with the physicists there, including , James Franck, Gustav Hertz, Robert Pohl, Max Planck, and Wilhelm Westphal.
During the first years Meitner worked with Hahn, they co-authored nine papers: three in 1908 and six in 1909. Together with Hahn, she discovered and developed a physical separation method known as radioactive recoil, in which a daughter nucleus is forcefully ejected as it recoils at the moment of decay. While Hahn was more concerned with discovering new elements (now known to be isotopes), Meitner was more interested in understanding their radiation. She observed that radioactive recoil, which had been discovered by Harriet Brooks in 1904, could be a new way of detecting radioactive substances. They soon discovered two more new isotopes, bismuth-211 and thallium-207. Meitner was particularly interested in beta particles. By this time, they were known to be electrons. Alpha particles were emitted with characteristic energy, and she expected that this would be true of beta particles too. Hahn and Meitner carefully measured the absorption of beta particles by aluminium, but the results were puzzling. In 1914, James Chadwick found that electrons emitted from the nucleus formed a continuous spectrum, but Meitner found this hard to believe, as it seemed to contradict quantum physics, which held that electrons in an atom can only occupy discrete energy states (quanta).
Kaiser Wilhelm Institute for Chemistry
In 1912, Hahn and Meitner moved to the newly founded Kaiser Wilhelm Institute (KWI) for Chemistry in Berlin. Hahn accepted an offer from Fischer to become a junior assistant in charge of its radiochemistry section, the first laboratory of its kind in Germany. The job came with the title of "professor" and a salary of 5,000 marks per annum (). Unlike the universities, the privately funded KWI had no policies excluding women, but Meitner worked without pay as a "guest" in Hahn's section. She may have encountered financial difficulties after the death of her father in 1910. Fearing she might return to Vienna, Planck appointed her as his assistant at the Institute for Theoretical Physics in the Friedrich Wilhelm University. As such, she marked his students' papers. It was her first paid position. Assistant was the lowest rung on the academic ladder, and Meitner was the first female scientific assistant in Prussia.