Question: Friedrich Hund, creator of Hund's rule of maximum multiplicity, is known for his work on what?

full_context: Document 1: Le Chatelier's principle: , Le Chatelier's principle (pronounced ), also called Chatelier's principle or "The Equilibrium Law", can be used to predict the effect of a change in conditions on a chemical equilibrium. The principle is named after Henry Louis Le Chatelier and sometimes Karl Ferdinand Braun who discovered it independently. It can be stated as:
Document 2: Carl Friedrich von Weizsäcker: Carl Friedrich Freiherr von Weizsäcker (28 June 1912 – 28 April 2007) was a German physicist and philosopher. He was the longest-living member of the team which performed nuclear research in Germany during the Second World War, under Werner Heisenberg's leadership. There is ongoing debate as to whether or not he and the other members of the team actively and willingly pursued the development of a nuclear bomb for Germany during this time.
Document 3: Heinrich Gerhard Kuhn: Heinrich Gerhard Kuhn {'1': ", '2': ", '3': ", '4': "} (10 March 1904 – 25 August 1994) was a British physicist. A graduate of the University of Göttingen, where he studied for his doctorate under the direction of James Franck, winner of the 1925 Nobel Prize for Physics, he left Germany after the Nazi Party came to power there in 1933, and moved to Britain, where relatives had settled, becoming a British subject in 1939. At the invitation of Frederick Alexander Lindemann, he worked for Imperial Chemical Industries at the Clarendon Laboratory in Oxford, where he studied hyperfine structure. During the Second World War, he worked on isotope separation for Tube Alloys and the Manhattan Project. He was the first physicist to become a fellow at Balliol College, Oxford, in 1950, and published textbooks on atomic spectra in German in 1934 and English in 1962.
Document 4: Friedrich Hund: Friedrich Hermann Hund (4 February 1896 – 31 March 1997) was a German physicist from Karlsruhe known for his work on atoms and molecules.
Document 5: Rudolf Fleischmann: Rudolf Fleischmann (1 May 1903 – 3 February 2002) was a German experimental nuclear physicist from Erlangen, Bavaria. He worked for Walther Bothe at the Physics Institute of the University of Heidelberg and then at the Institute for Physics of the Kaiser Wilhelm Institute for Medical Research. Through his association with Bothe, he became involved in the German nuclear energy project, also known as the Uranium Club; one of Fleischmann’s areas of interest was isotope separation techniques. In 1941 he was appointed associate professor of experimental physics at the newly established Reichsuniversität Straßburg, in France. Late in 1944, he was arrested under the American Operation Alsos and sent to the United States. After he returned to Germany 1946, he became Director of the State Physical Institute at the University of Hamburg and developed it as a center of nuclear research. In 1953, he took a position at the University of Erlangen and achieved "emeritus" status in 1969. He was a signatory of the Göttingen Manifesto in 1957.
Document 6: Franck–Condon principle: The Franck–Condon principle is a rule in spectroscopy and quantum chemistry that explains the intensity of vibronic transitions. Vibronic transitions are the simultaneous changes in electronic and vibrational energy levels of a molecule due to the absorption or emission of a photon of the appropriate energy. The principle states that during an electronic transition, a change from one vibrational energy level to another will be more likely to happen if the two vibrational wave functions overlap more significantly.
Document 7: Deslandres table: In electronic spectroscopy, constructing a Deslandres table is a useful method to assign vibronic transitions. In such a table, the frequencies of the lines seen in an electronic spectrum of a molecule are collected so that the differences in energy between adjacent columns or rows are all the same (within experimental error). Every line seen in the spectrum corresponds to a transition from the lower-lying electronic energy state to an excited electronic state (molecular electronic transition): associated with this, there are corresponding transitions between the vibrational levels of the two states, that give rise to many closely spaced lines. The intensity of the lines is governed by the Franck–Condon principle.
Document 8: 5-Dehydro-m-xylylene: 5-Dehydro-"m"-xylylene (DMX) is an aromatic organic triradical and the first known organic molecule to violate Hund's Rule.
Document 9: Hund's rule of maximum multiplicity: Hund's rule of maximum multiplicity is a rule based on observation of atomic spectra, which is used to predict the ground state of an atom or molecule with one or more open electronic shells. The rule states that for a given electron configuration, the lowest energy term is the one with the greatest value of spin multiplicity. This implies that if two or more orbitals of equal energy are available, electrons will occupy them singly before filling them in pairs. The rule, discovered by Friedrich Hund in 1925, is of important use in atomic chemistry, spectroscopy, and quantum chemistry, and is often abbreviated to Hund's rule, ignoring Hund's other two rules.
Document 10: Gerhard Hund: Gerhard Friedrich Hund (February 4, 1932 Leipzig) is a German chess player, mathematician and computer scientist.
Document 11: Hund's rules: In atomic physics, Hund's rules refers to a set of rules that German physicist Friedrich Hund formulated around 1927, which are used to determine the term symbol that corresponds to the ground state of a multi-electron atom. The first rule is especially important in chemistry, where it is often referred to as, simply, Hund's Rule.
Document 12: Arnold Sommerfeld: Arnold Johannes Wilhelm Sommerfeld, {'1': ", '2': ", '3': 'ForMemRS', '4': "} (] ; 5 December 1868 – 26 April 1951) was a German theoretical physicist who pioneered developments in atomic and quantum physics, and also educated and mentored a large number of students for the new era of theoretical physics. He served as PhD supervisor for many Nobel Prize winners in physics and chemistry (only J. J. Thomson's record of mentorship is comparable to his).
Document 13: Probability of occupation: In condensed matter physics, the probability of occupation shows how likely it is for a given energy level to be occupied. Fermions such as electrons follow a Fermi–Dirac distribution and bosons such as phonons and photons follow a Bose–Einstein distribution.
Document 14: Pontryagin's maximum principle: Pontryagin's maximum (or minimum) principle is used in optimal control theory to find the best possible control for taking a dynamical system from one state to another, especially in the presence of constraints for the state or input controls. It was formulated in 1956 by the Russian mathematician Lev Pontryagin and his students. It has as a special case the Euler–Lagrange equation of the calculus of variations.
Document 15: Werner Heisenberg: Werner Karl Heisenberg ( ; ] ; 5 December 1901 – 1 February 1976) was a German theoretical physicist and one of the key pioneers of quantum mechanics. He published his work in 1925 in a breakthrough paper. In the subsequent series of papers with Max Born and Pascual Jordan, during the same year, this matrix formulation of quantum mechanics was substantially elaborated. He is known for the Heisenberg uncertainty principle, which he published in 1927. Heisenberg was awarded the Nobel Prize in Physics for 1932 "for the creation of quantum mechanics".
ground_truth: known for his work on atoms and molecules.