George Placzek (; September 26, 1905 – October 9, 1955) was a Czech physicist. His work involved a fundamental theory of

Raman scattering In chemistry and physics, Raman scattering or the Raman effect () is the inelastic scattering of photons by matter, meaning that there is both an exchange of energy and a change in the light's direction. Typically this effect involves vibrationa ...

, molecular

spectroscopy Spectroscopy is the field of study that measures and interprets electromagnetic spectra. In narrower contexts, spectroscopy is the precise study of color as generalized from visible light to all bands of the electromagnetic spectrum. Spectro ...

in gases and liquids,

neutron The neutron is a subatomic particle, symbol or , that has no electric charge, and a mass slightly greater than that of a proton. The Discovery of the neutron, neutron was discovered by James Chadwick in 1932, leading to the discovery of nucle ...

physics and

mathematical physics Mathematical physics is the development of mathematics, mathematical methods for application to problems in physics. The ''Journal of Mathematical Physics'' defines the field as "the application of mathematics to problems in physics and the de ...

. Together with Otto Frisch, he suggested a direct experimental proof of

nuclear fission Nuclear fission is a reaction in which the nucleus of an atom splits into two or more smaller nuclei. The fission process often produces gamma photons, and releases a very large amount of energy even by the energetic standards of radioactiv ...

. Together with

Niels Bohr Niels Henrik David Bohr (, ; ; 7 October 1885 – 18 November 1962) was a Danish theoretical physicist who made foundational contributions to understanding atomic structure and old quantum theory, quantum theory, for which he received the No ...

and others, he was instrumental in clarifying the role of

uranium-235 Uranium-235 ( or U-235) is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a nuclear chain reaction. It is the only fissile isotope that exists in nat ...

for the possibility of nuclear chain reaction.

Biography

Placzek was born on September 26, 1905 into a wealthy Jewish family in

Brno Brno ( , ; ) is a Statutory city (Czech Republic), city in the South Moravian Region of the Czech Republic. Located at the confluence of the Svitava (river), Svitava and Svratka (river), Svratka rivers, Brno has about 403,000 inhabitants, making ...

Moravia Moravia ( ; ) is a historical region in the eastern Czech Republic, roughly encompassing its territory within the Danube River's drainage basin. It is one of three historical Czech lands, with Bohemia and Czech Silesia. The medieval and early ...

Austria-Hungary Austria-Hungary, also referred to as the Austro-Hungarian Empire, the Dual Monarchy or the Habsburg Monarchy, was a multi-national constitutional monarchy in Central Europe#Before World War I, Central Europe between 1867 and 1918. A military ...

(now the

Czech Republic The Czech Republic, also known as Czechia, and historically known as Bohemia, is a landlocked country in Central Europe. The country is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the south ...

), the grandson of

Chief Rabbi Chief Rabbi () is a title given in several countries to the recognized religious leader of that country's Jewish community, or to a rabbinic leader appointed by the local secular authorities. Since 1911, through a capitulation by Ben-Zion Meir ...

Baruch Placzek.
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He studied physics in

Prague Prague ( ; ) is the capital and List of cities and towns in the Czech Republic, largest city of the Czech Republic and the historical capital of Bohemia. Prague, located on the Vltava River, has a population of about 1.4 million, while its P ...

and

Vienna Vienna ( ; ; ) is the capital city, capital, List of largest cities in Austria, most populous city, and one of Federal states of Austria, nine federal states of Austria. It is Austria's primate city, with just over two million inhabitants. ...

. The scope of Placzek's trajectory around the world's physics centres in the 1930s was unique among his colleagues. He worked with Hans Bethe,

Edward Teller Edward Teller (; January 15, 1908 – September 9, 2003) was a Hungarian and American Theoretical physics, theoretical physicist and chemical engineer who is known colloquially as "the father of the hydrogen bomb" and one of the creators of ...

Rudolf Peierls Sir Rudolf Ernst Peierls, (; ; 5 June 1907 – 19 September 1995) was a German-born British physicist who played a major role in Tube Alloys, Britain's nuclear weapon programme, as well as the subsequent Manhattan Project, the combined Allied ...

Werner Heisenberg Werner Karl Heisenberg (; ; 5 December 1901 – 1 February 1976) was a German theoretical physicist, one of the main pioneers of the theory of quantum mechanics and a principal scientist in the German nuclear program during World War II. He pub ...

, Victor Weisskopf,

Enrico Fermi Enrico Fermi (; 29 September 1901 – 28 November 1954) was an Italian and naturalized American physicist, renowned for being the creator of the world's first artificial nuclear reactor, the Chicago Pile-1, and a member of the Manhattan Project ...

Lev Landau Lev Davidovich Landau (; 22 January 1908 – 1 April 1968) was a Soviet physicist who made fundamental contributions to many areas of theoretical physics. He was considered as one of the last scientists who were universally well-versed and ma ...

Edoardo Amaldi Edoardo Amaldi (5 September 1908 – 5 December 1989) was an Italian physicist. He coined the term "neutrino" in conversations with Enrico Fermi distinguishing it from the heavier "neutron". He has been described as "one of the leading nuclear p ...

, Emilio Segrè, Otto Frisch, Leon van Hove, and many other prominent physicists of his time. His wife, Els Placzek () was an ex-wife of physicist Hans von Halban. He lost all his relatives to

Holocaust The Holocaust (), known in Hebrew language, Hebrew as the (), was the genocide of History of the Jews in Europe, European Jews during World War II. From 1941 to 1945, Nazi Germany and Collaboration with Nazi Germany and Fascist Italy ...

, casting a tragic shadow on his life. During his stay in Landau's circle in

Kharkiv Kharkiv, also known as Kharkov, is the second-largest List of cities in Ukraine, city in Ukraine.

around 1937, Placzek witnessed the brutal reality of

Joseph Stalin Joseph Vissarionovich Stalin (born Dzhugashvili; 5 March 1953) was a Soviet politician and revolutionary who led the Soviet Union from 1924 until Death and state funeral of Joseph Stalin, his death in 1953. He held power as General Secret ...

's regime. His first-hand experience of this influenced the political opinions of his close friends, in particular, fathers of nuclear and thermonuclear bombs, Robert Oppenheimer and

. Later, Placzek was the only Czech with a leading position in the

Manhattan project The Manhattan Project was a research and development program undertaken during World War II to produce the first nuclear weapons. It was led by the United States in collaboration with the United Kingdom and Canada. From 1942 to 1946, the ...

, where he worked from 1943 till 1946 as a member of the British Mission; first in Canada as the leader of a theoretical division at the Montreal Laboratory and then (since May 1945) in Los Alamos, later replacing his friend Hans Bethe as the leader of the theoretical group. Since 1948, Placzek was a member of the

Institute for Advanced Study The Institute for Advanced Study (IAS) is an independent center for theoretical research and intellectual inquiry located in Princeton, New Jersey. It has served as the academic home of internationally preeminent scholars, including Albert Ein ...

in Princeton, United States. Unlike many trailblazers of nuclear physics, George Placzek did not leave his recollections or life story notes. Many new facts about Placzek's life and his family roots emerged in connection with a symposium held in Placzek's memory in 2005. Placzek's premature death in a hotel in

Zürich Zurich (; ) is the list of cities in Switzerland, largest city in Switzerland and the capital of the canton of Zurich. It is in north-central Switzerland, at the northwestern tip of Lake Zurich. , the municipality had 448,664 inhabitants. The ...

was very likely a suicide influenced by his long-time serious illness.

References

{{DEFAULTSORT:Placzek, George 1905 births 1955 deaths 1955 suicides Charles University alumni Moravian Jews Czech nuclear physicists Jewish physicists Manhattan Project people People associated with nuclear power People from the Margraviate of Moravia Scientists from Brno Czechoslovak Jews

Biography

See also

References