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An Institute at the Hebrew University of Jerusalem. Part of the Faculty of Mathematics and Natural Sciences, situated on the Edmund J. Safra Campus, Givat Ram, Jerusalem 91904, Israel. The Institute is the center for all research and teaching in the various fields of physics at the Hebrew University. These include astrophysics, high energy physics, quantum physics, nuclear physics, solid state physics, laser and plasma physics, biophysics and nanophysics. Both experimental and theoretical research is carried on in these fields.

Beginnings
In the year 1913 (a dozen years before the opening of the Hebrew University), first steps towards physics research in Jerusalem were taken by Chaim Weizmann. Weizmann, the President of the Zionist Organisation, and the major figure in the planning and founding of the Hebrew University contacted Leonard Ornstein, the known physicist from Utrecht, Holland, to prepare plans for physics research at the upcoming university. After the University was officially opened, he became the chairman of the physics group for several years, acting from his seat at Utrecht. In the year 1923, two years before its official opening, Albert Einstein gave a talk on Mont Scopus, the first campus of the University, on his relativity theory. This talk was considered by many as the opening talk of the Hebrew University. Einstein, who supported actively the foundation and development of the Hebrew University in Jerusalem since 1919 and throughout his entire life, was particularly active in helping to establish a good physics institute. The known mathematician, Abraham Halevi Fraenkel, who was on the governing board and served later as dean and rector of the University, invested great efforts looking for an excellent physicist to take the chair of theoretical physics in Jerusalem. He corresponded extensively with Einstein on this matter, seeking advice on the various possible candidates.

The first experimental physicist to be appointed (in 1928) was Shmuel Sambursky. He carried out his experiments in atomic spectroscopy during his visits to Ornstein's laboratory in Utrecht. His teaching duties consisted of the courses in classical experimental physics. In later years he became a well known historian of physics. In 1933 Ernst Alexander joined the experimental physics department and a year later – Guenther Wolfson. Both had to leave their posts in Germany due to the new racial laws, in spite of being highly appraised experimental physicists there. Both of them contributed substantially to the creation of an experimental infrastructure for physics research in Jerusalem. In 1934 the already known nuclear physicist George Placzek accepted a position in the department. After a few months in Jerusalem he left due to the lack of the experimental facilities which he considered necessary for his research.

During the years 1935-1938 several great physicists were offered the chair in theoretical physics. Felix Bloch, Eugene Wigner and Fritz London considered the offer seriously, everyone in his turn, after they had to leave their positions in Europe. They all declined after lengthy negotiations for differing personal reasons. Finally, Giulio (Yoel) Racah, a young professor in Pisa, Italy, was appointed. He was highly recommended by his teacher and mentor Enrico Fermi, as well as by Wolfgang Pauli, Niels Bohr and others. As a Zionist he was determined to come and teach in Hebrew in Jerusalem. He turned the theoretical physics department in Jerusalem into a world center for atomic spectroscopy. He died in an accident in 1965, age 56. Five years later, in 1970, experimental and theoretical physics departments were united into one new Institute named after Racah.

Early Research
In a series of groundbreaking papers Racah developed the mathematical methods, which are now textbook methods, for the calculation of the spectra of complex atoms. This work was carried out in Jerusalem in complete scientific isolation during the years of world war II. In this work he pioneered the use of symmetries and group theory for these calculations. Theoretical atomic spectroscopy was also the subject of most of his students and visitors. However, some of his best students started to apply his elaborate methods to the young science of nuclear spectroscopy. In Jerusalem, Nissan Zeldes, who became the world expert in the theory of nuclear masses, and Gideon Rakavy. Two of Racah's students, Amos de-Shalit and Igal Talmi, became the world leaders in theoretical nuclear spectroscopy. They founded the nuclear physics department at the Weizmann Institute in Rehovoth. As mentioned, experimental physics was carried out from the late 1920s, first by Sambursky in atomic spectroscopy then by Alexander and Wolfson in X-ray spectroscopy, crystallography and optics. In 1950 William Low (Ze'ev Lev), who was a student of Charles Townes in the United States, joined the experimental physics. He started new fields of research in Jerusalem. Starting to work on microwaves, he then set up a laboratory for magnetic resonance research. He also pioneered cryogenics and laser physics in Jerusalem. Nuclear magnetic resonance followed, including its medical application. Abraham Halperin and Abraham Many, two of Racah's early graduates, started new research directions in the physics of the solid state. They did experimental research on the optical and electrical properties of insulators and semiconductors, as well as the surface properties of solids. These fields of research were just starting to thrive along with the birth of the transistor. An important addition to the experimental group was Solly G. Cohen from England. He joined the physics in 1949 and became its first nuclear experimentalist measuring very long lived radionuclides as well as extremely short lived nuclear states. In the early sixties his interests shifted to the newly discovered Mossbauer effect, and established a research group which turned Jerusalem into a world center in this field.

Many graduates of the Racah Institute (and the physics departments which preceded it) became leading professors and scientists (including a Nobel Laureate) in Israel and all over the world. During its existence the Institute enjoyed visits of many important physicists from all over the world. Niels Bohr, Paul Dirac, Wolfgang Pauli, Robert Oppenheimer, John Wheeler and Stephen Hawking, to mention just a few. All Wolf Prize winners and a great number of Nobel Laureates were amongst the visitors.