Friedrich Hermann Hund (4 February 1896 – 31 March 1997) was a German

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 cau ...

from

Karlsruhe Karlsruhe ( ; ; ; South Franconian German, South Franconian: ''Kallsruh'') is the List of cities in Baden-Württemberg by population, third-largest city of the States of Germany, German state of Baden-Württemberg, after its capital Stuttgart a ...

known for his work on atoms and molecules. He is known for the Hund's rules to predict the

electron configuration In atomic physics and quantum chemistry, the electron configuration is the distribution of electrons of an atom or molecule (or other physical structure) in atomic or molecular orbitals. For example, the electron configuration of the neon ato ...

chemical element A chemical element is a chemical substance whose atoms all have the same number of protons. The number of protons is called the atomic number of that element. For example, oxygen has an atomic number of 8: each oxygen atom has 8 protons in its ...

s. His work on Hund's cases and

molecular orbital theory In chemistry, molecular orbital theory (MO theory or MOT) is a method for describing the electronic structure of molecules using quantum mechanics. It was proposed early in the 20th century. The MOT explains the paramagnetic nature of O2, whic ...

furthered the understanding of molecular structure.

Scientific career

Hund worked with such prestigious physicists as

Erwin Schrödinger Erwin Rudolf Josef Alexander Schrödinger ( ; ; 12 August 1887 – 4 January 1961), sometimes written as or , was an Austrian-Irish theoretical physicist who developed fundamental results in quantum field theory, quantum theory. In particul ...

Paul Dirac Paul Adrien Maurice Dirac ( ; 8 August 1902 – 20 October 1984) was an English mathematician and Theoretical physics, theoretical physicist who is considered to be one of the founders of quantum mechanics. Dirac laid the foundations for bot ...

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 ...

Max Born Max Born (; 11 December 1882 – 5 January 1970) was a German-British theoretical physicist who was instrumental in the development of quantum mechanics. He also made contributions to solid-state physics and optics, and supervised the work of a ...

, and

Walther Bothe Walther Wilhelm Georg Bothe (; 8 January 1891 – 8 February 1957) was a German physicist who shared the 1954 Nobel Prize in Physics with Max Born "for the coincidence method and his discoveries made therewith". He served in the military durin ...

. At that time, he was Born's assistant, working with quantum interpretation of band spectra of

diatomic molecule Diatomic molecules () are molecules composed of only two atoms, of the same or different chemical elements. If a diatomic molecule consists of two atoms of the same element, such as hydrogen () or oxygen (), then it is said to be homonuclear mol ...

After his studies of mathematics, physics, and geography in Marburg and Göttingen, he worked as a private lecturer for theoretical physics in the

University of Göttingen The University of Göttingen, officially the Georg August University of Göttingen (, commonly referred to as Georgia Augusta), is a Public university, public research university in the city of Göttingen, Lower Saxony, Germany. Founded in 1734 ...

(1925), professor in the

University of Rostock The University of Rostock () is a public university located in Rostock, Mecklenburg-Vorpommern, Germany. Founded in 1419, it is the third-oldest university in Germany. It is the oldest university in continental northern Europe and the Baltic Se ...

(1927),

Leipzig University Leipzig University (), in Leipzig in Saxony, Germany, is one of the world's oldest universities and the second-oldest university (by consecutive years of existence) in Germany. The university was founded on 2 December 1409 by Frederick I, Electo ...

(1929),

University of Jena The University of Jena, officially the Friedrich Schiller University Jena (, abbreviated FSU, shortened form ''Uni Jena''), is a public research university located in Jena, Thuringia, Germany. The university was established in 1558 and is cou ...

(1946), University Frankfurt (1951) and from 1957 again in Göttingen. Additionally, he stayed in Copenhagen (1926) 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 lectured on the atom at

Harvard University Harvard University is a Private university, private Ivy League research university in Cambridge, Massachusetts, United States. Founded in 1636 and named for its first benefactor, the History of the Puritans in North America, Puritan clergyma ...

(1928). He published more than 250 papers and essays in total. Hund made pivotal contributions to quantum theory - especially concerning the structure of the atom and of molecular spectra. In fact, Robert S. Mulliken, who was awarded the 1966

Nobel Prize in Chemistry The Nobel Prize in Chemistry () is awarded annually by the Royal Swedish Academy of Sciences to scientists in the various fields of chemistry. It is one of the five Nobel Prizes established by the will of Alfred Nobel in 1895, awarded for outst ...

for

, always proclaimed the great influence Hund's work had on his own and that he would have gladly shared the Nobel Prize with Hund. In recognition of the importance of Hund's contributions, molecular orbital theory is often referred to as the Hund–Mulliken MO theory. Hund's rule of maximum multiplicity is another eponym and, in 1926, Hund discovered the so-called tunnel effect or

quantum tunnelling In physics, quantum tunnelling, barrier penetration, or simply tunnelling is a quantum mechanical phenomenon in which an object such as an electron or atom passes through a potential energy barrier that, according to classical mechanics, shoul ...

. The Hund's cases, which are particular regimes in diatomic molecular

angular momentum coupling In quantum mechanics, angular momentum coupling is the procedure of constructing eigenstates of total angular momentum out of eigenstates of separate angular momenta. For instance, the orbit and spin of a single particle can interact through spi ...

, and Hund's rules, which govern atomic

s, are important in

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 ...

and

quantum chemistry Quantum chemistry, also called molecular quantum mechanics, is a branch of physical chemistry focused on the application of quantum mechanics to chemical systems, particularly towards the quantum-mechanical calculation of electronic contributions ...

. In chemistry, the first rule, Hund's rule of maximum multiplicity, is especially important and is often referred to as simply Hund's Rule. In 1927 he posed the question, subsequently called "Hund's paradox", of why chiral molecules such as sugars and amino acids are found in left or right handed forms but not superpositions. This paradox was resolved by the development of

quantum decoherence Quantum decoherence is the loss of quantum coherence. It involves generally a loss of information of a system to its environment. Quantum decoherence has been studied to understand how quantum systems convert to systems that can be expla ...

theory, which explains it as a manifestation of the

quantum Zeno effect In quantum mechanics, frequent measurements cause the quantum Zeno effect, a reduction in transitions away from the systems initial state, slowing a systems time evolution. Sometimes this effect is interpreted as "a system cannot change while you ...

Personal life

Hund married mathematician Ingeborg Seynsche (1905–1994) in

Barmen Barmen is a former industrial metropolis of the region of Bergisches Land, Germany, which merged with four other towns in 1929 to form the city of Wuppertal. Barmen, together with the neighbouring town of Elberfeld founded the first electric ...

on 17 March 1931. The family had six children: chess player and mathematician Gerhard Hund (1932–2024), Dietrich (1933–1939), Irmgard (b. 1934), Martin (1937–2018), Andreas (b. 1940) and Erwin (1941–2022). The chess woman grandmaster Barbara Hund (b. 1959) and chess player Isabel Hund (b. 1962) are his granddaughters. Hund is buried in Munich Waldfriedhof.

Honours

Hund was a member of the International Academy of Quantum Molecular Science. He was awarded the

Max Planck Medal The Max Planck Medal is the highest award of the German Physical Society , the world's largest organization of physicists, for extraordinary achievements in theoretical physics. The prize has been awarded annually since 1929, with few exceptions ...

in 1943.

Legacy

On the occasion of his 100th birthday, the book: Friedrich Hund: Geschichte der physikalischen Begriffe istory of Physical Concepts(Heidelberg, Berlin, Oxford), Spektrum, Akademie Verlag 1996, was published. A review was also written by Werner Kutzelnigg. Friedrich Hund's work and interest in the history of science was also discussed intensely in an interview conducted by Klaus Hentschel and

Renate Tobies Renate A. Tobies (born January 25, 1947) is a German mathematician and historian of mathematics known for her biographies of Felix Klein and Iris Runge. Education and career Tobies grew up in East Germany, and studied mathematics and chemistry ...

. In addition to the many honors bestowed upon him, Friedrich Hund became an honorary citizen of Jena/Saale, and a street in Jena was named after him. In June 2004, a part of a new building of the Physics Department in Göttingen was given the address Friedrich-Hund-Platz 1. The same name was chosen for the Institute for Theoretical Physics at the University of Göttingen.

Publications

* ''Versuch einer Deutung der großen Durchlässigkeit einiger Edelgase für sehr langsame Elektronen'', Dissertation, Universität Göttingen 1923 * ''Linienspektren und periodisches System der Elemente'', Habil.Schrift, Universität Göttingen, Springer 1927 * ''Allgemeine Quantenmechanik des Atom- und Molekelbaues'', in Handbuch der Physik, Band 24/1, 2nd edn., pp. 561–694 (1933) * ''Materie als Feld'', Berlin, Springer 1954 * ''Einführung in die Theoretische Physik'', 5 vols. 1944-51, Meyers Kleine Handbücher, Leipzig, Bibliographisches Institut, 1945, 1950/51 (vol. 1: Mechanik, vol. 2: Theorie der Elektrizität und des Magnetismus, vol. 3: Optik, vol. 4: Theorie der Wärme, vol. 5: Atom- und Quantentheorie) * ''Theoretische Physik'', 3 vols., Stuttgart Teubner, zuerst 1956-57, vol. 1: Mechanik, 5th edn. 1962, vol. 2: Theorie der Elektrizität und des Lichts, Relativitätstheorie, 4th edn. 1963, vol. 3: Wärmelehre und Quantentheorie, 3rd edn. 1966 * ''Theorie des Aufbaues der Materie'', Stuttgart, Teubner 1961 * ''Grundbegriffe der Physik'', Mannheim, Bibliographisches Institut 1969, 2nd edn. 1979 * ''Geschichte der Quantentheorie'', 1967, 2nd edn., Mannheim, Bibliographisches Institut 1975, 3rd edn. 1984; Eng. trans. 1974 * ''Quantenmechanik der Atome'', in Handbuch der Physik/Encyclopedia of Physics, Band XXXVI, Berlin, Springer 1956 * ''Die Geschichte der Göttinger Physik'', Vandenhoeck und Ruprecht 1987 (Göttinger Universitätsreden) * ''Geschichte der physikalischen Begriffe'', 1968, 2nd edn. (2 vols.), Mannheim, Bibliographisches Institut 1978 (vol. 1: Die Entstehung des mechanischen Naturbildes, vol. 2: Die Wege zum heutigen Naturbild), Spektrum Verlag 1996 * ''Göttingen, Kopenhagen, Leipzig im Rückblick'', in Fritz Bopp (ed.) ''Werner Heisenberg und die Physik unserer Zeit'', Braunschweig 1961 * See als
''Verzeichnis der Schriften Friedrich Hund (1896-1997)''
with about 300 entries

References

External links

Curriculum vitae, papers, diploma, honours, medals and decorations, photography, films and cassettes of Friedrich Hund
by Gerhard Hund {{DEFAULTSORT:Hund, Friedrich 1896 births 1997 deaths Commanders Crosses of the Order of Merit of the Federal Republic of Germany German men centenarians 20th-century German physicists Members of the International Academy of Quantum Molecular Science People from the Grand Duchy of Baden Scientists from Karlsruhe Academic staff of the University of Göttingen University of Jena alumni Leipzig University alumni University of Rostock alumni Winners of the Max Planck Medal Members of the German Academy of Sciences at Berlin Burials at Munich Waldfriedhof Members of the Göttingen Academy of Sciences and Humanities Recipients of the Cothenius Medal