Giulio (Yoel) Racah ( he, ג'וליו (יואל) רקח; February 9, 1909 – August 28, 1965) was an Italian–Israeli
physicist
A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe.
Physicists generally are interested in the root or ultimate caus ...
and
mathematician
A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems.
Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change.
History
On ...
.
He was Acting President of the
Hebrew University of Jerusalem
The Hebrew University of Jerusalem (HUJI; he, הַאוּנִיבֶרְסִיטָה הַעִבְרִית בִּירוּשָׁלַיִם) is a public research university based in Jerusalem, Israel. Co-founded by Albert Einstein and Dr. Chaim Weiz ...
from 1961 to 1962.
The crater
Racah on the Moon is named after him.
Biography
Giulio (Yoel) Racah was born in
Florence
Florence ( ; it, Firenze ) is a city in Central Italy and the capital city of the Tuscany region. It is the most populated city in Tuscany, with 383,083 inhabitants in 2016, and over 1,520,000 in its metropolitan area.Bilancio demografico an ...
,
Italy
Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical re ...
. He earned his BA from the
University of Florence
The University of Florence (Italian: ''Università degli Studi di Firenze'', UniFI) is an Italian public research university located in Florence, Italy. It comprises 12 schools and has around 50,000 students enrolled.
History
The first universi ...
in 1930, and continued his studies at
Rome
, established_title = Founded
, established_date = 753 BC
, founder = King Romulus (legendary)
, image_map = Map of comune of Rome (metropolitan city of Capital Rome, region Lazio, Italy).svg
, map_caption ...
with
Enrico Fermi
Enrico Fermi (; 29 September 1901 – 28 November 1954) was an Italian (later naturalized American) physicist and the creator of the world's first nuclear reactor, the Chicago Pile-1. He has been called the "architect of the nuclear age" and ...
.
In 1939, due to application of
Anti-Jewish laws in Italy, Racah
emigrated
Emigration is the act of leaving a resident country or place of residence with the intent to settle elsewhere (to permanently leave a country). Conversely, immigration describes the movement of people into one country from another (to permanentl ...
to the
British Mandate of Palestine British Mandate of Palestine or Palestine Mandate most often refers to:
* Mandate for Palestine: a League of Nations mandate under which the British controlled an area which included Mandatory Palestine and the Emirate of Transjordan.
* Mandatory P ...
. In the
1948 Arab–Israeli War
The 1948 (or First) Arab–Israeli War was the second and final stage of the 1948 Palestine war. It formally began following the end of the British Mandate for Palestine at midnight on 14 May 1948; the Israeli Declaration of Independence had ...
, Racah served as deputy commander of the Israeli forces defending
Mount Scopus
Mount Scopus ( he, הַר הַצּוֹפִים ', "Mount of the Watchmen/ Sentinels"; ar, جبل المشارف ', lit. "Mount Lookout", or ' "Mount of the Scene/Burial Site", or ) is a mountain (elevation: above sea level) in northeast Je ...
.
Racah died at the age of 56, apparently asphyxiated by gas from a faulty heater while visiting Florence.
Academic and scientific career
In 1937 Racah was appointed Professor of Physics at the
University of Pisa
The University of Pisa ( it, Università di Pisa, UniPi), officially founded in 1343, is one of the oldest universities in Europe.
History
The Origins
The University of Pisa was officially founded in 1343, although various scholars place ...
. In 1939, after his move to Palestine, he was appointed Professor of Theoretical Physics at the
Hebrew University of Jerusalem
The Hebrew University of Jerusalem (HUJI; he, הַאוּנִיבֶרְסִיטָה הַעִבְרִית בִּירוּשָׁלַיִם) is a public research university based in Jerusalem, Israel. Co-founded by Albert Einstein and Dr. Chaim Weiz ...
, He later became Dean of the Faculty of Sciences and finally
Rector
Rector (Latin for the member of a vessel's crew who steers) may refer to:
Style or title
*Rector (ecclesiastical), a cleric who functions as an administrative leader in some Christian denominations
*Rector (academia), a senior official in an edu ...
and acting President from 1961 to 1962, following
Benjamin Mazar and succeeded by
Eliahu Eilat
Eliahu Elath (Hebrew: אליהו אילת, born ''Ilya Menakhemovich Epstein''; 16 July 1903 – 21 June 1990) was an Israeli diplomat and Orientalist. In 1948 he became the first Israeli ambassador to the United States, and between 1950 and 195 ...
. The physics institute at the Hebrew University is named "
The Racah Institute of Physics".
Racah's research was mainly in the fields of
quantum physics
Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quantum chemistry, qua ...
and atomic
spectroscopy
Spectroscopy is the field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation. Matter wa ...
. He first devised a systematic general procedure for classifying the
energy level
A quantum mechanical system or particle that is bound—that is, confined spatially—can only take on certain discrete values of energy, called energy levels. This contrasts with classical particles, which can have any amount of energy. The te ...
s of open shell atoms, which remains to this day the accepted technique for practical calculations of
atomic structure
Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and a number of neutrons. Only the most common variety of hydrogen has no neutrons.
Every solid, liquid, gas, and ...
. This formalism was described in a monograph coauthored by his cousin
Ugo Fano
Ugo Fano (July 28, 1912 – February 13, 2001) was an Italian American physicist, notable for contributions to theoretical physics.
Biography
Ugo Fano was born into a wealthy Jewish family in Turin, Italy. His father was Gino Fano, a professo ...
(''Irreducible Tensorial Sets'', 1959).
Awards and recognition
In 1958, Racah was awarded the
Israel Prize
The Israel Prize ( he, פרס ישראל; ''pras israél'') is an award bestowed by the State of Israel, and regarded as the state's highest cultural honor.
History
The Israel Prize is awarded annually, on Israeli Independence Day, in a state cer ...
in exact sciences.
See also
*
Racah W-coefficient
*
Racah parameter
When an atom has more than one electron there will be some electrostatic repulsion between those electrons. The amount of repulsion varies from atom to atom, depending upon the number and spin of the electrons and the orbitals they occupy. The to ...
*
Racah polynomials In mathematics, Racah polynomials are orthogonal polynomials named after Giulio Racah, as their orthogonality relations are equivalent to his orthogonality relations for Racah coefficients.
The Racah polynomials were first defined by and are giv ...
*
Racah seniority number
*
Racah Lectures in Physics
''The Racah Lecture'' is annual memorial lecture given at The Racah Institute of Physics of the Hebrew University of Jerusalem commemorating Prof. Giulio Racah
Giulio (Yoel) Racah ( he, ג'וליו (יואל) רקח; February 9, 1909 – ...
*
List of Israel Prize recipients
This is a complete list of recipients of the Israel Prize from the inception of the Prize in 1953 through to 2022.
List
For each year, the recipients are, in most instances, listed in the order in which they appear on the official Israel Prize ...
*
Science and technology in Israel
Science and technology in Israel is one of the country's most developed sectors. Israel spent 4.3% of its gross domestic product (GDP) on civil research and development in 2015, the highest ratio in the world. In 2019, Israel was ranked the world' ...
References
External links
Timeline(at Racah Institute of Physics at Hebrew University)
Racah Crater">Link to Racah Crater on Google Moon
{{DEFAULTSORT:Racah, Giulio
20th-century_Italian_mathematicians
20th-century_Israeli_physicists
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20th-century Israeli physicists
20th-century Israeli mathematicians
20th-century Italian physicists
Italian emigrants to Mandatory Palestine
Italian Zionists
20th-century Italian Jews
University of Florence alumni
University of Pisa faculty
Hebrew University of Jerusalem faculty
Israel Prize in exact science recipients
Israel Prize in exact science recipients who were mathematicians
Israel Prize in exact science recipients who were physicists
Members of the Israel Academy of Sciences and Humanities
Scientists from Florence
1909 births
1965 deaths
Jewish physicists
Presidents of universities in Israel
Italian refugees