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Giulio Racah was born in 1909 in the city of Florence in Italy. His parents came from very well connected families, who had contributed their share of distinguished personalities to Italian Jewry. After graduating with distinction from the Humanities Gymnasium, he registered to study engineering. After a year, on the advice of his instructors, who had rapidly become aware of his exceptional abilities in the field of mathematics, he transferred to the study of physics, and received a doctorate in physics from the University of Florence in 1930.
The years preceding the Second World War were years of breakthrough for physics in Italy. A group of young researchers, several of whom later became Nobel Prize laureates, worked together at the University of Rome close to Enrico Fermi, who headed the group which designed and built the first atomic reactor, in 1942, at the University of Chicago. For a year Racah was Fermi's assistant in Rome, and then continued in Zurich to study for a further year under Wolfgang Pauli, one of the great physicists of the twentieth century. He then began teaching Theoretical Physics at the Universities of Florence and Pisa, and in 1937, following a country-wide competition, was appointed Associate Professor at the University of Pisa, and was one of the youngest professors in Italy at that time.
In 1934 Racah had visited Palestine and was taken with Zionism and its achievements. When the racist laws were published in Italy in 1938 and he was dismissed from his university position, Racah decided to immigrate to Palestine. The Hebrew University of Jerusalem had at the time been looking for a number of years for a theoretical physicist of standing to join its Physics Department. Encouraged by Prof. Chaim Weizmann, Racah emigrated to Israel in 1939 with his mother, and joined the University as a Full Professor of Theoretical Physics.
In 1940 Racah married Zmira, nee Mani, who later bore him a daughter and two sons. In 1942 he joined the "Haganah" (Jewish Defence Fighters) and completed a course for Squad Commanders at Kiryat Anavim. At the outbreak of the war of Independence, he was Deputy Commander of the Mt. Scopus area, that was already then, as it was later in the Six-Day War, a Jewish enclave surrounded by Arab held territory. From March 1948, until the end of the war Racah was the only Scientific Military Commander in Jerusalem. He made his home in Jerusalem and refused, after the end of the war in Europe, to return to his position in Pisa.
During the time that Racah was a student, the Quantum Theory was developed. Certain calculations in the field of quantum electronics had still not been worked out precisely by scientists at the time. Racah succeeded in producing accurate conclusions, thanks to his special analytical abilities and his striving for scientific perfection.
Racah produced his great, original contributions to physics in Jerusalem, precisely at a time when it was cut off for five years from the mainstream of physics because of the Second World War. These contributions grew out of a response to problems which he encountered in his study of atomic spectroscopy, and the papers which he published in this field between 1942 and 1949, are today regarded as exemplary works In recognition of his scientific achievements, Racah was awarded many honorary degrees and distinctions. He was made an Honorary Member of the Weizmann Institute of Science (1959), Honorary Doctor of Science of the University of Manchester (1961) and Honorary Foreign Member of the American Academy of Arts and Sciences (1963). He was awarded the Israel Prize in the Natural Sciences (1958) and received many other honours. The International Astronomy Association named one of the craters on the moon in his name (1970).
In the last years of his life, Racah served as Rector of the Hebrew University of Jerusalem. On completing this appointment Racah was full of plans for recommencing his scientific work. Together with his group of theoretical spectroscopy scientists in Jerusalem, he planned to participate in an international conference on Atomic spectroscopy which was about to take place in Amsterdam in honour of the centenary of the birth of the Dutch physicist, Zeeman. Two days after leaving the country Racah met his death in Florence, in the house where he was born and grew up, from a gas leak in an old heating installation.
