Giulio Racah

Giulio Racah was born in Florence on February 9, 1909. His maternal family claimed that its Italian ancestry reached back to the destruction of the Second Temple, although the sources present this as family tradition rather than documented genealogy.[1][2]

Racah studied physics in Rome under Enrico Fermi and in Pisa under Wolfgang Pauli.[1] A history of Fermi's Rome circle also identifies Racah as one of its temporary visitors, later known for his work on atomic spectra and the coefficients that bear his name.[3]

At age 28, Racah was appointed professor at the University of Pisa.[1] He held a physics professorship there for two years before leaving Italy in 1939 amid the Fascist regime's anti-Jewish laws.[2]

On September 5, 1938, King Vittorio Emanuele III signed the first decree implementing Italy's anti-Jewish laws, titled "Measures to Defend Race in Fascist Schools." The subsequent university purge affected 96 full and associate professors, 133 assistants and researchers, hundreds of lecturers, and approximately 1,500 students.[4] A Library of Congress-hosted study gives similar provisional faculty totals of 96 ordinary professors, 133 assistants, and about 200 independent lecturers.[5]

The laws ended Racah's academic career in Italy. After two years as a professor at Pisa, he immigrated to Palestine in 1939 to escape Fascist Italy's anti-Jewish measures and joined the Hebrew University of Jerusalem.[2] The hostility surrounding Jewish academics was already explicit: the Library of Congress-hosted study reports that the antisemitic physicist Ivo Ranzi had said he "sentiva puzza di ebreo" — "smelled a Jew" — in Racah's presence.[5]

Racah's connection to Zionism predated his forced departure. He had visited Palestine in 1934 and made his farm outside Pisa available to the Zionist Organization as an agricultural training center. His settlement in Jerusalem in 1939 therefore fulfilled an earlier commitment as well as providing refuge from persecution.[1][6]

At the Hebrew University of Jerusalem, Racah headed the Department of Theoretical Physics and pursued research in atomic spectroscopy. His work helped give the department an international reputation.[1][6]

Racah's best-known scientific contributions were the Racah method and the Racah coefficient W. The method became an effective approach to studying nuclear structure, while the W coefficient found broad application in research on nuclear radiation. Leading scientific institutions published books of tables based on the coefficient.[1][2]

Racah also trained a notable group of students in the Hebrew University's direct master's-degree track in natural sciences: Yigal Talmi, Amos de-Shalit, Israel Pelah, Gideon Yekutieli, Gabi Goldring, and Uri Haber-Shaim.[7][8] Their studies were interrupted by the War of Independence, but they completed their master's degrees under Racah's supervision after the war.[7]

Racah's lectures made a strong impression on Talmi and his contemporaries. After Talmi received his master's degree, Racah offered him a teaching-assistant position and proposed supervising a doctorate in atomic spectroscopy. Talmi instead pursued doctoral work with Wolfgang Pauli in Zurich.[9]

Racah's influence extended beyond the Hebrew University. His reputation attracted scientists to Israel, and graduates he trained formed much of the Weizmann Institute of Science's Department of Nuclear Physics.[1][6]

During Israel's War of Independence, Racah served as deputy commander of the Haganah on Mount Scopus in Jerusalem. He also led research into munitions that could be produced from raw materials available in the besieged city.[1][2]

Racah joined the Science Corps, the defense-research organization that preceded Rafael, and headed its group of physicists in Jerusalem.[7][8] He assigned his six master's students to develop and assemble a recoilless gun for the early Israel Defense Forces. The project, code-named "Loreta," was not completed before the war ended.[8]

Another project began with an Italian proposal for a hollow charge intended to penetrate armor or a fortified wall. Racah presented the idea to the students, for nearly all of whom the Science Corps work was a first experience with applied physics.[7]

After the fighting, the six students returned to their studies and completed their master's degrees. Several later became leading figures in Israeli nuclear physics and helped build the Weizmann Institute's research program.[7][8]

Racah served as dean of the Hebrew University's Faculty of Natural Sciences.[7] Biographical entries state that he was elected rector in 1961.[1][6] Other sources describe an additional or differently titled role: the Center for Israel Education calls him acting president, while an Encyclopedia.com history lists Giulio Racah as acting president for 1961–1962.[2][10]

His advancement reflected more than his individual research. By that time, Racah had helped make the theoretical-physics department internationally known and had trained students whose careers extended his influence into other Israeli scientific institutions.[1][7]

Racah received the Israel Prize for natural sciences in 1958 in recognition of his scientific work.[1][2]

His name also entered astronomical nomenclature when a crater on the Moon was named for him, complementing the continuing use of the Racah method and coefficient in physics.[2]

Racah died on August 28, 1965, at age 56 while visiting Florence, the city of his birth. The Center for Israel Education states that his death was believed to have resulted from asphyxiation caused by a faulty gas heater.[2]

Racah's scientific legacy rests principally on the methods that carry his name. The Racah method provided an influential approach to atomic and nuclear structure, while the Racah coefficient W became widely useful in calculations involving nuclear radiation.[1][2]

His institutional legacy was equally important. Research in atomic spectroscopy under his leadership helped give the Hebrew University's theoretical-physics department an international reputation, and graduates trained by him formed much of the Weizmann Institute's nuclear-physics department.[1][6] His six master's students became part of the pioneering generation that developed nuclear-physics research in the young State of Israel.[7][8]

Racah's Zionism also found practical expression. Before leaving Italy, he provided his farm to the Zionist Organization for agricultural training. In Jerusalem, he combined university work with Haganah service and defense research during the War of Independence.[1][2]

Together, his research, teaching, institution-building, and wartime service made him an important figure in the development of Israeli physics. The Israel Prize, the lunar crater bearing his name, and the continued use of his scientific methods preserve different aspects of that legacy.

Sources use different titles for Racah's senior university leadership. Biographical entries say that he was elected rector in 1961.[1][6] The Center for Israel Education calls him acting president, and an Encyclopedia.com history lists him as acting president in 1961–1962.[2][10] The available material does not establish whether these were overlapping positions or differences in terminology.

The reported cause of his death is also qualified rather than definitive. The Center for Israel Education says it was believed to have been asphyxiation from a faulty gas heater.[2]