On the path of human exploration of nuclear energy, the stars are shining, and Lise Meitner is a dazzling one. Starting with Planck and Hahn, two physicist assistants, she became the first German professor of physics, introduced the concept of "nuclear fission" for the first time, and at the peak of her scholarship, refused to participate in the Manhattan Project to use nuclear energy for war.
"She never lost her personality and humanity," City University of Hong Kong Chair Professor Chan Kwan Wing wrote about the nuclear physicist's life.
Written by | Chen Guanrong
Source: Jizhi Club
She was an Austrian-born nuclear physicist, the first female full professor of physics in German history, and the first female member of the Austrian Academy of Sciences, named Lise Meitner (1878.11.7–1968.10.27).
It is well known that some of the elements that appear later in the periodic table are named in honor of great scientists. For example, element Curium (cm) No. 96 commemorates the Curie couple , Element 99 gallium (einsteinium, es) commemorates Einstein , Element 104 rutherfordium (rf)
In memory of Rutherford, and so on. In May 1994, the International Union of Pure and Applied Chemistry named element 109 meitnerium (mt) in honor of the physicist Meitner.
Physicist Lizzie Meitner (1878-1968)
Born on 7 November 1878 in Vienna, Austria, into a Jewish lawyer's family, Elise, Lizé was the third of eight children. Since girls were not admitted to the higher secondary schools at the time, Meitner attended a private school. In 1901 she passed the examination and received her diploma at the Higher Secondary School of the Academy of Sciences in Vienna. In the same year, she entered the University of Vienna, where she studied physics, mathematics and philosophy. Later in college, Meitner studied radiophysics under the tutelage of Ludwig Boltzmann. In 1906 she graduated with a doctoral thesis entitled "Thermal Conductivity in Uneven Matter", becoming the second female Doctorate in Vienna and the second female Doctorate in physics in the world (the first was elsa Neumann of the University of Berlin, 1899). She then spent a year at the Institute of Theoretical Physics at the University of Vienna. In 1907, she came to Berlin, then the capital of the Prussian Empire, to work at friedrich wihelm university (the predecessor of Humboldt University of Berlin). Her mentor was Max Planck and Otio Hahn (1879-1968), a chemist who would later work with her for more than three decades. Hahn is a PhD student at two British Nobel Laureates in Chemistry, William Ramsay, and a postdoc at Ernest Rutherford. He himself became famous for discovering several radioactive elements. Prussia of that era did not allow women to enter universities for higher education and hold high positions, and Meitner had to study and work in the laboratory of the Institute of Chemistry in Hahn as an "unpaid assistant". Either way, Meitner and Hahn worked together very happily. Meitner said: "Hahn and I are about the same age and are informal. I realized that whatever I needed to know, I could ask him as much as I could. And he has a great reputation in the field of radioactivity, and I'm sure he can teach me a lot. In fact, Meitner began publishing scientific papers in collaboration with Hahn shortly after joining the job. Records show that in 1908 they published 3 papers together, followed by 6 papers together in 1909, and have not been interrupted for several years.
Hahn and Meitner worked in the Chemistry Laboratory of the Royal Wilhelm Institute in Berlin (the Royal Wilhelm Institute berlin was one of the first institutes founded in 1911 by the Kaiser-wilhelm-gesellschaft zur förderung der wissenschaften)
From 1912 onwards, Meitner also served as Planck's teaching assistant, changing assignments for students. Meitner recalls: "He accepted me graciously and invited me to his house shortly afterwards. On my first visit, he said to me, "You're already a doctor, what else do you want?" I replied that I wished I could understand physics more realistically. But he only said some kind words and did not go further into the topic. I naturally think he doesn't have too high a rating for female students. But at the time, people probably thought the same thing. In Planck's case, Meitner remained unpaid until he became a full member of the Institute of Chemistry in 1913. Planck was the physicist who had the most important influence on Meitner after Boltzmann and later became her mentor and friend. In 1914, World War I broke out. Hahn went to the front lines and took part in the research on the response to poison gas weapons. Meitner also joined the Austrian Field Hospital as an X-ray nurse and cared for wounded soldiers.
Toward the end of the war in 1917, Meitner returned to Berlin and established the Department of Physics at the Royal William Institute while serving as head of the department until 1938. During this time, she was awarded the position of professor at the University of Berlin in 1922 and became a distinguished professor in 1926. She was the first female full professor of physics in Germany.
After the war ended in 1918, Hahn returned to the lab and continued to work with Meitner. Soon, together, they discovered the radioactive element protactinium-231 (pa), which was later designated 91. This element was first discovered in 1913 by Polish-American chemists Kasimir Fajans and assistant Goering (oswald Göhring), but pa-231 is the longest-lived isotope of the congener. During this time, much of Meitner's own research was an exploration of α and β rays, revealing the nature of radioactivity and its effects on other elements. In 1924, the Prussian Academy of Sciences awarded Meitner the Leibniz Medal in recognition of her scientific contributions.
Between 1924 and 1938, Hahn and his two assistants, Metner and Fritz Strassmann, were fruitful in discovering several radioactive metamorphosis elements.
By 1938, however, World War II was about to break out. Germany annexed Austria, turning Meitner into a German citizen and putting his life at risk for his Jewish identity. She then left Germany and came to Sweden via the Netherlands and Denmark. With the assistance of Niels Bohr, Meitner entered the laboratory of the Swedish Academy of Sciences (svenska akademien), where he worked until 1946. In 1947, Meitner transferred to the Royal Institute of Technology in Sweden to lead a nuclear physics group to continue experimental research. She later became a Swedish citizen.
In Sweden, Meitner maintained academic discussion and exchange with Hahn's letters. In the summer of 1938, Hahn wrote a letter saying that he and Strathman had discovered a "rupture" of atomic nuclei and speculated that uranium (uranium-239, u) had broken down into barium (barium, ba) and technetium (tc), and was eager to hear from Meitner. After more than half a year of experimental research, in 1939 Meitner and his nephew Otto Frisch jointly published a paper in the journal Nature titled "Neutron-induced Uranium Fission: A New Nuclear Reaction," which perfectly explained the phenomenon of "rupture" observed by Hahn. The article is to the effect that the total mass of the fissioned nuclei is smaller than that of the pre-fission uranium nuclei, and this small mass difference is converted into energy. Using Einstein's theory of relativity formula = 2, they calculated that each fissioned nucleus released 200 million electron volts of energy, about twenty million times the energy released at the time of the tnt explosion. They called this process fission and introduced the concept of "nuclear fission." This history suggests that Meitner and Frisch were the first scientists in the world to know from theory and experiment that nuclear fission can unleash enormous amounts of energy. It is said that after Meitner told Bohr about his new discovery, Bohr was stunned that he had missed the opportunity: "Ah, we are so stupid! Bohr was so agitated that he almost delayed his ship to the United States. After arriving in the United States, Bohr informed Enrico Fermi of the University of Chicago. Subsequently, in 1942, Fermi built the world's first controlled nuclear reactor in the United States.
Bohr (front second from left) and Meitner (front right)
In 1939, World War II broke out. Military politicians and scientists on both sides of the war realized that nuclear fission could be used to make powerful bombs, and began to develop them secretly. In 1943, Meitner was invited by the Manhattan Project of the Allies to develop nuclear weapons, and asked her to go to the United States to work on the atomic bomb. She flatly refused, saying: "I have nothing to do with the bomb. Years later, she felt relieved and said, "As a physicist, I don't have the slightest shame about my conscience." ”
In 1944, Hahn was awarded the Nobel Prize in Chemistry. Regrettably, the Nobel Committee forgot about two aides, Metner and Strassman, who had made equal contributions. Hahn himself was of course well aware of the contributions of Meitner and Strassmann, and therefore mentioned in his Nobel Prize speech: "Immediately after the publication of my first article on the production of barium from uranium, Lizer Meitner and Otto Frisch published a newsletter using Bohr's nuclear model, revealing that this phenomenon may be due to the split of heavy nuclei into two light nuclei, with the same total charge as before fission. Meitner and Frisch also estimated the enormous amount of energy released by this reaction from the elemental mass loss curve... Meitner and Frisch soon demonstrated that those radioactive products previously thought to be transuranic elements were not actually transuranic elements, but fragments produced when they split... The term 'nuclear fission' comes from Metner and Frisch. Hahn also gave 10,000 of the 121,000 SEK prize to Strassmann and a larger portion to Meitner. But Meitner donated all of the money to the aid committee for atomic physicists chaired by Einstein.
Later, however, Hahn did not mention Meitner and Strassmann in many public events and speeches. This made Meitner sad. In a letter to a friend, she said: "I was quite upset when I found out that Hahn didn't mention me at all in the interview, nor did he talk about our thirty years of cooperation. The long-term cooperation and friendship between the two has since cracked. But she "never said a word to Hahn's face that embarrassed hahn." Later, Meitner was nominated for several Nobel Prizes, one of which was recommended by Hahn, but to no avail.
After the end of World War II in 1945, although Hahn repeatedly invited Meitner to return to Germany to work, she politely refused. She and Hahn disagree on their views on World War II: Hahn emphasized Nazi oppression during the war, the Allied occupation of Germany, and the hardships of german life after the war, while Meitner attacked Nazi crimes and denounced Germany's devastation to other nations. She was critical of Hahn in these respects. At that time, Hahn was extremely prestigious in Germany and even in the international scientific community, and Meitner slowly moved away from the inner circle of the scientific community, so the two gradually drifted apart. But they both opposed the manufacture and use of nuclear weapons, and they agreed on this basic point, so the two did not part ways. In his memoirs, Hahn insisted that Meitner was his lifelong good friend.
In the 1950s and 1960s, Meitner returned to Germany frequently, visiting Hahn and his family from time to time. In 1962, when Meitner and Hahn reunited at the "Hahn-Meitner Institute" in Berlin, they left behind a valuable photograph of "a smile and a grudge".
Reunion at the "Hahn-Meitner Institute" in Berlin in 1962
In 1945, Meitner was elected a foreign member of the Swedish Academy of Sciences, and became a naturalized member after 1951. In 1946, the 68-year-old Meitner was invited to visit the United States, to Harvard, Princeton, Columbia and other famous colleges and universities to speak, visited Einstein, Fermi, Rabbi, Chadwick, Yang Zhenning, Li Zhengdao and other Nobel Laureates and Weil and other famous mathematicians, had dinner with then President Truman, and was also named "Woman of the Year" by the American press. In 1947, Meitner won the Vienna Prize for Science and was elected a member of the Austrian Academy of Sciences, becoming Austria's first female academician. She was then awarded the Planck Medal of the German Physical Society in 1949 and elected a Foreign Fellow of the Royal Society, the Hahn Prize of the German Chemical Society in 1955, the German Scientist's Highest Honor Award from the President of Germany in 1957, and an Honorary Foreign Fellow of the American Academy of Sciences and Arts in 1960. In 1966, Meitner shared the Fermi Prize from the U.S. Atomic Energy Commission with Hahn and Strassman. In addition, Meitner holds honorary doctorates from several universities in the United States and Sweden.
Lizé Meitner commemorative stamps issued by Austria and Germany
Meitner's personal life has always been simple and uneventful. She never married, liked to be alone, and did not leave anecdotal gossip. According to Hahn and Planck, Meitner worked extremely intently and diligently. She herself said: "I love physics, and it's hard to imagine life without physics." ”
In 1960, at the age of 82, Meitner moved to Cambridge, England, to live with the family of her nephew Frisch. Hahn died on July 28, 1968. In order to avoid Maitner's upset, no one ever told her the bad news. On October 27 of the same year, Meitner also passed away. Both died at the age of 90. Meitner was buried in the Hampshire, England, in a small village of Bramley st. James Parish Church Cemetery, adjacent to the tomb of her brother Walter, who died in 1964.
Inspired by Meitner's lifelong commitment to the peaceful use of the physical achievements of nuclear fission that she discovered, posterity inscribed a condolence on her tombstone: "A physicist who never lost her humanity."
Lizzie Meitner's tombstone
After Meitner's death, there were earthen pits on the moon and Venus named after Meitner, and the solar system's asteroid 6999 had its own name, Meta. In 2000, the European Physical Society established the Lisé Meitner Prize for Nuclear Science. In 2006, Sweden also established the Meitner Prize in Physics. In addition, the Austrian and German Physical Societies have established lizel Meitner lecture series, and a major nuclear energy project of the American Foundation for Advanced Research is also named after Meitner.
"I love physics, and it's hard to imagine life without physics." —Lizel Meitner
Statue of Lisse Meitner (Humboldt University of Berlin)
This article is reproduced with permission from the WeChat public account "Jizhi Club".