Enrico Fermi
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Enrico Fermi was an Italian physicist, who created the worlds first nuclear reactor, the Chicago Pile-1. He has been called the architect of the age and the architect of the atomic bomb. He was one of the few physicists to excel both theoretically and experimentally and he made significant contributions to the development of quantum theory, nuclear and particle physics, and statistical mechanics. Fermis first major contribution was to statistical mechanics, today, particles that obey the exclusion principle are called fermions. Later Pauli postulated the existence of an invisible particle emitted along with an electron during beta decay. Fermi took up this idea, developing a model that incorporated the postulated particle and his theory, later referred to as Fermis interaction and still later as weak interaction, described one of the four fundamental forces of nature. Fermi left Italy in 1938 to escape new Italian Racial Laws that affected his Jewish wife Laura Capon and he emigrated t
1.
Enrico Fermi (1901–1954)
2.
Enrico Fermi as a student in Pisa
4.
Laura and Enrico Fermi at the Institute for Nuclear Studies, Los Alamos, 1954
Nuclear fission
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In nuclear physics and nuclear chemistry, nuclear fission is either a nuclear reaction or a radioactive decay process in which the nucleus of an atom splits into smaller parts. The fission process often produces free neutrons and gamma photons, Frisch named the process by analogy with biological fission of living cells. It is a reaction which can release large amounts of energy both as electromagnetic radiation and as kinetic energy of the fragments. In order for fission to produce energy, the binding energy of the resulting elements must be less negative than that of the starting element. Fission is a form of nuclear transmutation because the fragments are not the same element as the original atom. The two nuclei produced are most often of comparable but slightly different sizes, typically with a ratio of products of about 3 to 2. Most fissions are binary fissions, but occasionally, three positively charged fragments are produced, in a ternary fission, the smallest of these fragments
1.
The mushroom cloud produced by Tsar Bomba, currently the largest man-made nuclear device detonated in history, next to other mushroom clouds of various nuclear devices.
Manhattan Project
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The Manhattan Project was a research and development undertaking during World War II that produced the first nuclear weapons. It was led by the United States with the support of the United Kingdom, from 1942 to 1946, the project was under the direction of Major General Leslie Groves of the U. S. Army Corps of Engineers. Nuclear physicist J. Robert Oppenheimer was the director of the Los Alamos Laboratory that designed the actual bombs, the Army component of the project was designated the Manhattan District, Manhattan gradually superseded the official codename, Development of Substitute Materials, for the entire project. Along the way, the project absorbed its earlier British counterpart, the Manhattan Project began modestly in 1939, but grew to employ more than 130,000 people and cost nearly US $2 billion. Over 90% of the cost was for building factories and to produce material, with less than 10% for development. Research and production took place at more than 30 sites across the Unite
4.
Groves confers with
James Chadwick, the head of the British Mission
California Institute of Technology
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The California Institute of Technology is a private doctorate-granting university located in Pasadena, California, United States. The vocational and preparatory schools were disbanded and spun off in 1910, the university is one among a small group of Institutes of Technology in the United States which is primarily devoted to the instruction of technical arts and applied sciences. Caltech has six divisions with strong emphasis on science and engineering, managing $332 million in 2011 in sponsored research. Its 124-acre primary campus is located approximately 11 mi northeast of downtown Los Angeles, first-year students are required to live on campus, and 95% of undergraduates remain in the on-campus House System at Caltech. Although Caltech has a tradition of practical jokes and pranks. The Caltech Beavers compete in 13 intercollegiate sports in the NCAA Division IIIs Southern California Intercollegiate Athletic Conference, Caltech is frequently cited as one of the worlds best universiti
1.
Throop Polytechnic Institute, Pasadena, Calif, 1908, on its original campus at downtown Pasadena.
2.
Caltech Seal
3.
Throop Hall, 1912
4.
Caltech entrance at 1200 E California Blvd. On the left is East Norman Bridge Laboratory of Physics and on the right is the Alfred Sloan Laboratory of Mathematics and Physics.
Raman effect
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Raman scattering or the Raman effect /ˈrɑːmən/ is the inelastic scattering of a photon by molecules which are excited to higher vibrational or rotational energy levels. It was discovered by C. V. Raman and K. S. Krishnan in liquids, the effect had been predicted theoretically by Adolf Smekal in 1923. When photons are scattered from an atom or molecule, most photons are elastically scattered, a small fraction of the scattered photons are scattered by an excitation, with the scattered photons having a frequency different from, and usually lower than, that of the incident photons. In a gas, Raman scattering can occur with a change in energy of a due to a transition to another energy level. Chemists are primarily concerned with the transitional Raman effect, the inelastic scattering of light was predicted by Adolf Smekal in 1923. In 1922, Indian physicist C. V, the Raman effect was first reported by C. V. Raman and K. S. Krishnan, and independently by Grigory Landsberg and Leonid Mandelsta
Dinitrogen
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Nitrogen is a chemical element with symbol N and atomic number 7. It was first discovered and isolated by Scottish physician Daniel Rutherford in 1772, although Carl Wilhelm Scheele and Henry Cavendish had independently done so at about the same time, Rutherford is generally accorded the credit because his work was published first. Nitrogen is the lightest member of group 15 of the periodic table, the name comes from the Greek πνίγειν to choke, directly referencing nitrogens asphyxiating properties. It is an element in the universe, estimated at about seventh in total abundance in the Milky Way. At standard temperature and pressure, two atoms of the element bind to form dinitrogen, a colourless and odorless diatomic gas with the formula N2, dinitrogen forms about 78% of Earths atmosphere, making it the most abundant uncombined element. Nitrogen occurs in all organisms, primarily in amino acids, in the nucleic acids, the human body contains about 3% nitrogen by mass, the fourth most abu
3.
Nitrogen discharge (spectrum) tube
4.
Table tennis ball made from nitrocellulose.
Atomic nucleus
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After the discovery of the neutron in 1932, models for a nucleus composed of protons and neutrons were quickly developed by Dmitri Ivanenko and Werner Heisenberg. Almost all of the mass of an atom is located in the nucleus, protons and neutrons are bound together to form a nucleus by the nuclear force. The diameter of the nucleus is in the range of 6985175000000000000♠1.75 fm for hydrogen to about 6986150000000000000♠15 fm for the heaviest atoms and these dimensions are much smaller than the diameter of the atom itself, by a factor of about 23,000 to about 145,000. The branch of physics concerned with the study and understanding of the nucleus, including its composition. The nucleus was discovered in 1911, as a result of Ernest Rutherfords efforts to test Thomsons plum pudding model of the atom, the electron had already been discovered earlier by J. J. Knowing that atoms are electrically neutral, Thomson postulated that there must be a charge as well. In his plum pudding model, Thomson
Spectroscopy
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Spectroscopy /spɛkˈtrɒskəpi/ is the study of the interaction between matter and electromagnetic radiation. Historically, spectroscopy originated through the study of visible light dispersed according to its wavelength, later the concept was expanded greatly to include any interaction with radiative energy as a function of its wavelength or frequency. Spectroscopic data is represented by an emission spectrum, a plot of the response of interest as a function of wavelength or frequency. Spectroscopy and spectrography are terms used to refer to the measurement of radiation intensity as a function of wavelength and are used to describe experimental spectroscopic methods. Spectral measurement devices are referred to as spectrometers, spectrophotometers, spectrographs or spectral analyzers, daily observations of color can be related to spectroscopy. Neon lighting is an application of atomic spectroscopy. Neon and other noble gases have characteristic emission frequencies, neon lamps use colli
1.
Analysis of white light by
dispersing it with a prism is an example of spectroscopy.
2.
A huge diffraction grating at the heart of the ultra-precise
ESPRESSO spectrograph.
Sapienza University of Rome
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The Sapienza University of Rome, also called simply Sapienza or the University of Rome, is a collegiate research university located in Rome, Italy. Formally known as Università degli Studi di Roma La Sapienza, it is the largest European university by enrollments and one of the oldest in history, the University is also the most prestigious Italian university and also the best ranked in Southern Europe. The biggest part of the Italian ruling class studied at this University and he introduced a new tax on wine in order to raise funds for the university, the money was used to buy a palace which later housed the SantIvo alla Sapienza church. However, the Universitys days of splendour came to an end during the sack of Rome in 1527, when the studium was closed and the professors dispersed, Pope Paul III restored the university shortly after his ascension to the pontificate in 1534. In the 1650s the university known as Sapienza, meaning wisdom. University students were newly animated during th
1.
Palazzo della Sapienza, former home of the University until 1935.
2.
Sapienza University of Rome
Edoardo Amaldi
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Edoardo Amaldi was an Italian physicist. Amaldi was born in Carpaneto Piacentino, son of Ugo Amaldi, professor of mathematics at the University of Padua, Amaldi graduated under the supervision of Enrico Fermi and was his main collaborator until 1938, when Fermi left Italy for the United States. In 1939, Amaldi was drafted into the Royal Italian Army and he was the general secretary of CERN at its early stages when operations were still provisional, before Septembers 1954 official foundation. He pioneered in Europe the search for gravitational waves and he also wrote historical-scientific books, like for example, the biography of his missing friend Ettore Majorana. He was elected a Foreign Honorary Member of the Soviet Academy of Sciences in 1958 and American Academy of Arts, in 1963 he became foreign member of the Royal Netherlands Academy of Arts and Sciences. Amaldi died unexpectedly on 5 December 1989, still in activity, while he was president of the Accademia dei Lincei. The third
1.
Edoardo Amaldi in 1960
2.
The Via Panisperna Boys, including Edoardo Amaldi (center), circa 1934
Ettore Majorana
–
Ettore Majorana was an Italian theoretical physicist who worked on neutrino masses. On March 25,1938, he disappeared under mysterious circumstances while going by ship from Palermo to Naples, the Majorana equation and Majorana fermions are named after him. In 2006, the Majorana Prize was established in his memory, there are several categories of scientists in the world, those of second or third rank do their best but never get very far. Then there is the first rank, those who make important discoveries, but then there are the geniuses, like Galilei and Newton. Majorana was born in Catania, Sicily, mathematically gifted, he was very young when he joined Enrico Fermis team in Rome as one of the Via Panisperna boys, who took their name from the street address of their laboratory. His uncle Quirino Majorana was also a physicist and he began his university studies in engineering in 1923 but switched to physics in 1928 at the urging of Emilio Segrè. His first papers dealt with problems in at
1.
A portrait of Ettore Majorana
2.
Handwritten notes preparatory to the equation in infinite components
Orso Mario Corbino
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Orso Mario Corbino was an Italian physicist and politician. He served as the minister for education in 1921 and as the minister for economy in 1921 and he also served as professor in Messina and in Rome. Noted for his studies of the influence of magnetic fields on the motion of electrons in metals. As director of the Institute of physics he was the supervisor of Enrico Fermi, Edoardo Amaldi, Franco Rasetti and Emilio Segrè, Bruno Pontecorvo, Oscar DAgostino, Ettore Majorana
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Orso Mario Corbino, 1920-1937
Neutron
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The neutron is a subatomic particle, symbol n or n0, with no net electric charge and a mass slightly larger than that of a proton. Protons and neutrons, each with approximately one atomic mass unit, constitute the nucleus of an atom. Their properties and interactions are described by nuclear physics, the nucleus consists of Z protons, where Z is called the atomic number, and N neutrons, where N is the neutron number. The atomic number defines the properties of the atom. The terms isotope and nuclide are often used synonymously, but they are chemical and nuclear concepts, the atomic mass number, symbol A, equals Z+N. For example, carbon has atomic number 6, and its abundant carbon-12 isotope has 6 neutrons, some elements occur in nature with only one stable isotope, such as fluorine. Other elements occur with many stable isotopes, such as tin with ten stable isotopes, even though it is not a chemical element, the neutron is included in the table of nuclides. Within the nucleus, protons
2.
The
quark structure of the neutron. The color assignment of individual quarks is arbitrary, but all three colors must be present. Forces between quarks are mediated by
gluons.
3.
Cold neutron source providing neutrons at about the temperature of liquid hydrogen
Radioactivity
–
A material containing such unstable nuclei is considered radioactive. Certain highly excited short-lived nuclear states can decay through neutron emission, or more rarely, however, for a collection of atoms, the collections expected decay rate is characterized in terms of their measured decay constants or half-lives. This is the basis of radiometric dating, the half-lives of radioactive atoms have no known upper limit, spanning a time range of over 55 orders of magnitude, from nearly instantaneous to far longer than the age of the universe. A radioactive nucleus with spin can have no defined orientation. If there are multiple particles produced during a single decay, as in decay, their relative angular distribution. Such a parent process could be a previous decay, or a nuclear reaction, the decaying nucleus is called the parent radionuclide, and the process produces at least one daughter nuclide. Except for gamma decay or internal conversion from an excited state. When the number of ch
1.
Pierre and Marie Curie in their Paris laboratory, before 1907
3.
Taking an X-ray image with early
Crookes tube apparatus in 1896. The Crookes tube is visible in the centre. The standing man is viewing his hand with a
fluoroscope screen; this was a common way of setting up the tube. No precautions against radiation exposure are being taken; its hazards were not known at the time.
4.
Gamma-ray energy spectrum of uranium ore (inset). Gamma-rays are emitted by decaying
nuclides, and the gamma-ray energy can be used to characterize the decay (which nuclide is decaying to which). Here, using the gamma-ray spectrum, several nuclides that are typical of the decay chain of 238 U have been identified: 226 Ra, 214 Pb, 214 Bi.
Atomic bomb
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A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from small amounts of matter. The first test of a bomb released the same amount of energy as approximately 20,000 tons of TNT. The first thermonuclear bomb test released the same amount of energy as approximately 10 million tons of TNT, a thermonuclear weapon weighing little more than 2,400 pounds can produce an explosive force comparable to the detonation of more than 1.2 million tons of TNT. A nuclear device no larger than traditional bombs can devastate a city by blast, fire. Nuclear weapons are considered weapons of destruction, and their use. Nuclear weapons have been used twice in nuclear warfare, both times by the United States against Japan near the end of World War II, the bombings resulted in the deaths of approximately 200,000 civilians and military personnel from acute injur
2.
Nuclear weapons
3.
Edward Teller, often referred to as the "father of the hydrogen bomb"
Bruno Pontecorvo
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Bruno Pontecorvo was an Italian nuclear physicist, an early assistant of Enrico Fermi and the author of numerous studies in high energy physics, especially on neutrinos. A convinced communist, he defected to the Soviet Union in 1950, the prestigious Pontecorvo Prize was instituted in his memory in 1995. The fourth of eight children of a wealthy Italian family, Pontecorvo studied physics at the University of Rome La Sapienza, under Fermi, in 1934 he participated in Fermis famous experiment showing the properties of slow neutrons that led the way to the discovery of nuclear fission. He moved to Paris in 1934, where he conducted research under Irène, influenced by his cousin, Emilio Sereni, he joined the French Communist Party, as did his sisters Guiliana and Laura and brother Gillo. The Italian Fascist regimes 1938 racial laws against Jews caused his family members to leave Italy for Britain, France and the United States. When the German Army closed in on Paris during the Second World Wa
1.
Bruno Pontecorvo in the 1950s
Manhattan project
–
The Manhattan Project was a research and development undertaking during World War II that produced the first nuclear weapons. It was led by the United States with the support of the United Kingdom, from 1942 to 1946, the project was under the direction of Major General Leslie Groves of the U. S. Army Corps of Engineers. Nuclear physicist J. Robert Oppenheimer was the director of the Los Alamos Laboratory that designed the actual bombs, the Army component of the project was designated the Manhattan District, Manhattan gradually superseded the official codename, Development of Substitute Materials, for the entire project. Along the way, the project absorbed its earlier British counterpart, the Manhattan Project began modestly in 1939, but grew to employ more than 130,000 people and cost nearly US $2 billion. Over 90% of the cost was for building factories and to produce material, with less than 10% for development. Research and production took place at more than 30 sites across the Unite
4.
Groves confers with
James Chadwick, the head of the British Mission
Laval University
–
Université Laval is a French-language, public research university in Quebec City, Quebec, Canada. The university began as the Séminaire de Québec, which was founded in 1663 by François de Montmorency-Laval, a member of the House of Laval, during the French Regime the institution mainly trained priests to serve in New France. After the Conquest of 1760, the British expanded education in Canada to include the liberal arts, French Canadians had at the time no opportunity to pursue higher education, and Bishop Bourget of Montreal suggested expanding the Séminaire de Québec into Université Laval. Louis Casault, a priest who taught physics at the Séminaire de Québec, went to Europe to seek a royal charter and study the best university systems there. The Séminaire de Québec was granted a charter on December 8,1852, by Queen Victoria, at the request of Lord Elgin, creating Université Laval with the rights. The charter was signed in 1852, Pope Benedict XV approved the plan and authorized the in
1.
This article may require
copy editing for non-native language. You can assist by editing it. (June 2015)
2.
Laval University
3.
The Old Séminaire de Québec today
4.
Université Laval School of Architecture
Quebec City
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Quebec City, French, Ville de Québec, officially Québec) is the capital city of the Canadian province of Quebec. Founded in 1608 by Samuel de Champlain, Quebec City is one of the oldest cities in North America. The citys landmarks include the Château Frontenac, a hotel which dominates the skyline, and La Citadelle, the National Assembly of Quebec, the Musée national des beaux-arts du Québec, and the Musée de la civilisation are found within or near Vieux-Québec. Thus, Québec is officially spelled with an accented é in both Canadian English and French, although the accent is not used in common English usage. Quebec City is one of the oldest European settlements in North America, while many of the major cities in Latin America date from the sixteenth century, among cities in Canada and the U. S. few were created earlier than Quebec City. Also, Quebecs Old Town is the only North American fortified city north of Mexico whose walls still exist, French explorer Jacques Cartier built a fort a
3.
Quebec Settlement, 1608
4.
Port of Quebec City in the early 20th century
Naturalized citizen
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Naturalization is the legal act or process by which a non-citizen in a country may acquire citizenship or nationality of that country. It may be done by a statute, without any effort on the part of the individual, or it may involve an application, an oath or pledge of allegiance is also sometimes required. In some rare cases, laws for mass naturalization were passed, since World War II, the increase in international migrations created a new category of refugees, most of them economic refugees. The Peoples Republic of China gives citizenship to persons with one or two parents with Chinese nationality who have not taken residence in other countries, the country also gives citizenship to people born on its territory to stateless people who have settled there. Furthermore, individuals may apply for nationality if they have a relative with Chinese nationality, if they have settled in China. In practice, only few people gain Chinese citizenship, as of 2010, the naturalization process starts
1.
A judge swears in a new citizen-to-be. New York, NY 1910
4.
Servicemembers are sworn in as citizens aboard the
USS Midway in 2009
Johns Hopkins University
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The Johns Hopkins University is an American private research university in Baltimore, Maryland. Founded in 1876, the university was named for its first benefactor, the American entrepreneur, abolitionist and his $7 million bequest—of which half financed the establishment of The Johns Hopkins Hospital—was the largest philanthropic gift in the history of the United States at that time. Daniel Coit Gilman, who was inaugurated as the institutions first president on February 22,1876, led the university to revolutionize higher education in the U. S. by integrating teaching and research. Adopting the concept of a school from Germanys ancient Heidelberg University. Johns Hopkins is organized into 10 divisions on campuses in Maryland and Washington, D. C. with international centers in Italy, China, and Singapore. The two undergraduate divisions, the Krieger School of Arts and Sciences and the Whiting School of Engineering, are located on the Homewood campus in Baltimores Charles Village neighbo
2.
The Johns Hopkins University
4.
Hopkins Hall circa 1885, on the original downtown Baltimore campus
Baltimore
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Baltimore is the largest city in the U. S. state of Maryland, and the 29th-most populous city in the country. It was established by the Constitution of Maryland and is not part of any county, thus, it is the largest independent city in the United States, with a population of 621,849 as of 2015. As of 2010, the population of the Baltimore Metropolitan Area was 2.7 million, founded in 1729, Baltimore is the second largest seaport in the Mid-Atlantic. Baltimores Inner Harbor was once the leading port of entry for immigrants to the United States. With hundreds of identified districts, Baltimore has been dubbed a city of neighborhoods, in the War of 1812, Francis Scott Key wrote The Star-Spangled Banner, later the American national anthem, in Baltimore. More than 65,000 properties, or roughly one in three buildings in the city, are listed on the National Register, more than any city in the nation. The city has 289 properties listed on the National Register of Historic Places, the historical
1.
Sixth Regiment fighting railroad strikers, July 20, 1877
Trilobite
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Trilobites are a fossil group of extinct marine arachnomorph arthropods that form the class Trilobita. Trilobites form one of the earliest known groups of arthropods, Trilobites finally disappeared in the mass extinction at the end of the Permian about 250 million years ago. The trilobites were among the most successful of all early animals, by the time trilobites first appeared in the fossil record, they were already highly diversified and geographically dispersed. Because trilobites had wide diversity and an easily fossilized exoskeleton, a fossil record was left behind. The study of fossils has facilitated important contributions to biostratigraphy, paleontology, evolutionary biology. Trilobites are often placed within the arthropod subphylum Schizoramia within the superclass Arachnomorpha, Trilobites had many lifestyles, some moved over the sea bed as predators, scavengers, or filter feeders, and some swam, feeding on plankton. Most lifestyles expected of modern marine arthropods a
Fossil
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Fossils are the preserved remains or traces of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous rock formations and sedimentary layers is known as the fossil record. The study of fossils across geological time, how they were formed, such a preserved specimen is called a fossil if it is older than some minimum age, most often the arbitrary date of 10,000 years. The observation that fossils were associated with certain rock strata led early geologists to recognize a geological timescale in the 19th century. The development of dating techniques in the early 20th century allowed geologists to determine the numerical or absolute age of the various strata. Like extant organisms, fossils vary in size from microscopic, even single bacterial cells one micrometer in diameter, to gigantic, such as dinosaurs, Fossils may also consist of the marks left behind by the organism while it was alive,
1.
Silicified (replaced with silica) fossils from the Road Canyon Formation (Middle Permian of Texas).
Alps
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The mountains were formed over tens of millions of years as the African and Eurasian tectonic plates collided. Extreme shortening caused by the event resulted in marine sedimentary rocks rising by thrusting and folding into high mountain peaks such as Mont Blanc, Mont Blanc spans the French–Italian border, and at 4,810 m is the highest mountain in the Alps. The Alpine region area contains about a hundred peaks higher than 4000 metres, the altitude and size of the range affects the climate in Europe, in the mountains precipitation levels vary greatly and climatic conditions consist of distinct zones. Wildlife such as live in the higher peaks to elevations of 3,400 m. Evidence of human habitation in the Alps goes back to the Palaeolithic era, a mummified man, determined to be 5,000 years old, was discovered on a glacier at the Austrian–Italian border in 1991. By the 6th century BC, the Celtic La Tène culture was well established, Hannibal famously crossed the Alps with a herd of elephant
3.
An "alp" refers to a high mountain pasture, often with a structure, such as this one on the south side of the Alps, where cows are taken for grazing.
4.
The Alps extend in an arc from France in the south and west to Slovenia in the east, and from Monaco in the south to Germany in the north.
Raman scattering
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Raman scattering or the Raman effect /ˈrɑːmən/ is the inelastic scattering of a photon by molecules which are excited to higher vibrational or rotational energy levels. It was discovered by C. V. Raman and K. S. Krishnan in liquids, the effect had been predicted theoretically by Adolf Smekal in 1923. When photons are scattered from an atom or molecule, most photons are elastically scattered, a small fraction of the scattered photons are scattered by an excitation, with the scattered photons having a frequency different from, and usually lower than, that of the incident photons. In a gas, Raman scattering can occur with a change in energy of a due to a transition to another energy level. Chemists are primarily concerned with the transitional Raman effect, the inelastic scattering of light was predicted by Adolf Smekal in 1923. In 1922, Indian physicist C. V, the Raman effect was first reported by C. V. Raman and K. S. Krishnan, and independently by Grigory Landsberg and Leonid Mandelsta
Gerhard Herzberg
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Herzbergs main work concerned atomic and molecular spectroscopy. Herzberg served as Chancellor of Carleton University in Ottawa, Ontario, Herzberg was born in Hamburg, Germany on December 25,1904 to Albin H. Herzberg and Ella Biber. He had a brother, Walter, who was born in January 1904. Herzberg started Vorschule late, after contracting measles, Gerhard and his family were atheists and kept this fact hidden. His father died in 1914, at 43 years of age, after having suffered from dropsy, Herzberg graduated Vorschule shortly after his fathers death. Initially, Herzberg considered a career in astronomy, but his application to the Hamburg Observatory was returned advising him not to pursue a career in the field without private financial support. After completing high school at the Gelehrtenschule des Johanneums, Herzberg continued his education at Darmstadt University of Technology with the help of a private scholarship, degree under Hans Rau in 1928. During the presentation speech, it wa
Walter Heitler
–
Walter Heinrich Heitler was a German physicist who made contributions to quantum electrodynamics and quantum field theory. He brought chemistry under quantum mechanics through his theory of valence bonding and he then became an assistant to Max Born at the Institute for Theoretical Physics at the Georg-August University of Göttingen. Heitler completed his Habilitation, under Born, in 1929, in that year, he was let go by the university because he was Jewish. These institutes were located at the LMU, under Arnold Sommerfeld, the University of Göttingen, under Max Born, furthermore, Werner Heisenberg and Born had just recently published their trilogy of papers which launched the matrix mechanics formulation of quantum mechanics. These papers immediately put the personnel at the theoretical physics institutes onto applying these new tools to understanding atomic. In Zurich, with Fritz London, Heitler applied the new mechanics to deal with the saturable, nondynamic forces of attraction and
1.
Walter Heinrich Heitler (1904-1981)
Spin isomers of hydrogen
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Molecular hydrogen occurs in two isomeric forms, one with its two proton spins aligned parallel, the other with its two proton spins aligned antiparallel. These two forms are referred to as spin isomers, since they differ not in chemical structure. Parahydrogen is in an energy state than is orthohydrogen. At room temperature and thermal equilibrium, thermal excitation causes hydrogen to consist of approximately 75% orthohydrogen, when hydrogen is liquified at low temperature, there is a slow spontaneous transition to a predominantly para ratio, with the released energy having implications for storage. Essentially pure parahydrogen form can be obtained at low temperatures. Each hydrogen molecule consists of two hydrogen atoms linked by a covalent bond, if we neglect the small proportion of deuterium and tritium which may be present, each hydrogen atom consists of one proton and one electron. Each proton has a magnetic moment, which is associated with the protons spin of 1/2. In the H2 m
1.
Molar Rotational Energies
2.
Spin isomers of molecular hydrogen
3.
Molar Heat Capacities
Quantum mechanics
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Quantum mechanics, including quantum field theory, is a branch of physics which is the fundamental theory of nature at small scales and low energies of atoms and subatomic particles. Classical physics, the physics existing before quantum mechanics, derives from quantum mechanics as an approximation valid only at large scales, early quantum theory was profoundly reconceived in the mid-1920s. The reconceived theory is formulated in various specially developed mathematical formalisms, in one of them, a mathematical function, the wave function, provides information about the probability amplitude of position, momentum, and other physical properties of a particle. In 1803, Thomas Young, an English polymath, performed the famous experiment that he later described in a paper titled On the nature of light. This experiment played a role in the general acceptance of the wave theory of light. In 1838, Michael Faraday discovered cathode rays, Plancks hypothesis that energy is radiated and absorbed
1.
Max Planck is considered the father of the quantum theory.
2.
Solution to
Schrödinger's equation for the hydrogen atom at different energy levels. The brighter areas represent a higher probability of finding an
electron
Pauli exclusion principle
–
The Pauli exclusion principle is the quantum mechanical principle that states that two or more identical fermions cannot occupy the same quantum state within a quantum system simultaneously. This principle was formulated by Austrian physicist Wolfgang Pauli in 1925 for electrons, a more rigorous statement is that the total wave function for two identical fermions is antisymmetric with respect to exchange of the particles. This means that the function changes its sign if the space. The Pauli exclusion principle describes the behavior of all fermions, while bosons are subject to other principles, fermions include elementary particles such as quarks, electrons and neutrinos. Additionally, baryons such as protons and neutrons and some atoms are fermions, as such, the Pauli exclusion principle underpins many properties of everyday matter, from its large-scale stability, to the chemical behavior of atoms. Half-integer spin means that the angular momentum value of fermions is ℏ = h /2 π times
Rotational spectroscopy
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Rotational spectroscopy is concerned with the measurement of the energies of transitions between quantized rotational states of molecules in the gas phase. The spectra of molecules can be measured in absorption or emission by microwave spectroscopy or by far infrared spectroscopy. The rotational spectra of non-polar molecules cannot be observed by those methods, analytical expressions can be derived for the fourth category, asymmetric top, for rotational levels up to J=3, but higher energy levels need to be determined using numerical methods. In the presence of a field there is Stark splitting which allows molecular electric dipole moments to be determined. An important application of spectroscopy is in exploration of the chemical composition of the interstellar medium using radio telescopes. Rotational spectroscopy has primarily used to investigate fundamental aspects of molecular physics. It is a precise tool for the determination of molecular structure in gas phase molecules. It can
1.
Part of the rotational spectrum of
trifluoroiodomethane, CF 3 I. Each rotational transition is labeled with the quantum numbers, J, of the final and initial states, and is extensively split by the effects of
nuclear quadrupole coupling with the 127 I nucleus.
Nuclear spin
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In quantum mechanics and particle physics, spin is an intrinsic form of angular momentum carried by elementary particles, composite particles, and atomic nuclei. Spin is one of two types of angular momentum in mechanics, the other being orbital angular momentum. In some ways, spin is like a vector quantity, it has a definite magnitude, all elementary particles of a given kind have the same magnitude of spin angular momentum, which is indicated by assigning the particle a spin quantum number. The SI unit of spin is the or, just as with classical angular momentum, very often, the spin quantum number is simply called spin leaving its meaning as the unitless spin quantum number to be inferred from context. When combined with the theorem, the spin of electrons results in the Pauli exclusion principle. Wolfgang Pauli was the first to propose the concept of spin, in 1925, Ralph Kronig, George Uhlenbeck and Samuel Goudsmit at Leiden University suggested an physical interpretation of particles
2.
Schematic diagram depicting the spin of the neutron as the black arrow and magnetic field lines associated with the
neutron magnetic moment. The neutron has a negative magnetic moment. While the spin of the neutron is upward in this diagram, the magnetic field lines at the center of the dipole are downward.
3.
Wolfgang Pauli
Werner Heisenberg
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Werner Karl Heisenberg 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. In 1927 he published his uncertainty principle, upon which he built his philosophy, Heisenberg was awarded the Nobel Prize in Physics for 1932 for the creation of quantum mechanics. He was a principal scientist in the Nazi German nuclear weapon project during World War II and he travelled to occupied Copenhagen where he met and discussed the German project with Niels Bohr. Following World War II, he was appointed director of the Kaiser Wilhelm Institute for Physics and he was director of the institute until it was moved to Munich in 1958, when it was expanded and renamed the Max Planck Institute for Physics and Astrophysics. He studied physics and mathematics fro
2.
Heisenberg, Habilitation 1924
Charles Doolittle Walcott Medal
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Charles Doolittle Walcott Medal is an award presented by the National Academy of Sciences every five years to promote research and study in the fields of Precambrian and Cambrian life and history. The medal was established and endowed in 1934 by the Walcott Fund, the medal was sculpted by Laura Gardin Fraser. Since 2008 the award has been linked to the Stanley Miller Medal, each medal is supplemented by a $10,000 award. Source, NAS NAS Award in Early Earth and Life Sciences
1.
Charles Doolittle Walcott Medal
United States National Academy of Sciences
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The National Academy of Sciences is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering, as a national academy, new members of the organization are elected annually by current members, based on their distinguished and continuing achievements in original research. Election to the National Academies is one of the highest honors in the scientific field, members serve pro bono as advisers to the nation on science, engineering, and medicine. The group holds a congressional charter under Title 36 of the United States Code, … to provide scientific advice to the government whenever called upon by any government department. The Academy receives no compensation from the government for its services, as of 2016, the National Academy of Sciences includes about 2,350 members and 450 foreign associates. It employed about 1,100 staff in 2005, the current members annually e
1.
National Academy of Sciences
2.
The Keck Center of the National Academies in
Washington, D.C., one of several facilities where the National Academy of Sciences maintains offices.
Nature (journal)
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Nature is an English multidisciplinary scientific journal, first published on 4 November 1869. Nature claims a readership of about 3 million unique readers per month. The journal has a circulation of around 53,000. There are also sections on books and arts, the remainder of the journal consists mostly of research papers, which are often dense and highly technical. There are many fields of research in which important new advances, the papers that have been published in this journal are internationally acclaimed for maintaining high research standards. In 2007 Nature received the Princess of Asturias Award for Communications, the enormous progress in science and mathematics during the 19th century was recorded in journals written mostly in German or French, as well as in English. Britain underwent enormous technological and industrial changes and advances particularly in the half of the 19th century. In addition, during this period, the number of popular science periodicals doubled from
1.
Nature
2.
First title page, November 4, 1869.
3.
Nature Materials, a specialised journal from Nature Publishing Group.
Smithsonian Institution Archives
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The Smithsonian Institution Archives is the archives of the Smithsonian Institution. SIA is located in Washington, D. C, united States, and maintains the archives related to the history of the 19 museums and galleries, the National Zoological Park,9 research facilities, and the people of the Smithsonian. SIAs collections consist of material related to art, history, science. This includes collections about expeditions, biographies, and general history about the Smithsonian Institution, in 1891, William Jones Rhees, Chief Clerk of the Smithsonian Institution, became Keeper of the Archives. Current records and historical files were maintained by Office of the Secretarys administrative staff through the middle of the 20th century, John F. Jameson III became Archivist in 1958. His successor, John DeGurse, Jr. served from 1960-1964, beginning in 1965, Smithsonian Archivist Samuel T. The Archives were physically relocated to the Smithsonian Castle, and received separate line-item funding, nat
1.
Smithsonian Institution Archives
Virtual International Authority File
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The Virtual International Authority File is an international authority file. It is a joint project of national libraries and operated by the Online Computer Library Center. The project was initiated by the US Library of Congress, the German National Library, the National Library of France joined the project on October 5,2007. The project transitions to a service of the OCLC on April 4,2012, the aim is to link the national authority files to a single virtual authority file. In this file, identical records from the different data sets are linked together, a VIAF record receives a standard data number, contains the primary see and see also records from the original records, and refers to the original authority records. The data are available online and are available for research and data exchange. Reciprocal updating uses the Open Archives Initiative Protocol for Metadata Harvesting protocol, the file numbers are also being added to Wikipedia biographical articles and are incorporated int
Integrated Authority File
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The Integrated Authority File or GND is an international authority file for the organisation of personal names, subject headings and corporate bodies from catalogues. It is used mainly for documentation in libraries and increasingly also by archives, the GND is managed by the German National Library in cooperation with various regional library networks in German-speaking Europe and other partners. The GND falls under the Creative Commons Zero license, the GND specification provides a hierarchy of high-level entities and sub-classes, useful in library classification, and an approach to unambiguous identification of single elements. It also comprises an ontology intended for knowledge representation in the semantic web, available in the RDF format
