RACAH, GIULIO (Yoel; 1909–1965), Israeli physicist, born in Florence, Italy. On his mother's side, Racah's family claimed to trace its ancestry in Italy back to the destruction of the Second Temple. Racah studied in Rome under Enrico Fermi and in Pisa under Wolfgang Pauli. At the age of 28 he was appointed professor at the University of Pisa. An ardent Zionist, he placed his farm outside Pisa for use by the Zionist Organization as an agricultural training center. He first visited Palestine in 1934, and on settling in Jerusalem in 1939 headed the department of theoretical physics of the Hebrew University. Here, Racah began his studies of atomic spectroscopy which gained the department an international reputation. During the Israel War of Independence he served as deputy commander of the Haganah on Mount Scopus and led research on munitions that could be produced from the raw materials available in the besieged city. The "Racah method" of spectroscopy has been recognized as one of the most effective methods of studying all types of nuclear structure. His "Racah coefficient W" has wide application in research on nuclear radiations, and it is the basis of books of tables published by many of the world's leading scientific institutions. In 1958 Racah was awarded the Israel Prize for natural sciences. His reputation attracted notable scientists to Israel, and the department of nuclear physics at the Weizmann Institute of Science was built up mainly by graduates trained by Racah. In 1961 Racah was elected rector of the Hebrew University. He died while visiting Florence.
PIASH, section of sciences, no. 2 (1966); I. Talmi, in: Nuclear Physics, 83 (1966), 1–8, incl. bibl.; Journal of the Optical Society of America, 56 (Feb. 1966), 268.