Ion-mobility spectrometry is an analytical technique used to separate and identify ionized molecules in the gas phase based on their mobility in a carrier buffer gas. Though employed for military or security purposes, such as detecting drugs and explosives, the technique has many laboratory analytical applications, including the analysis of both small and large biomolecules. IMS instruments are sensitive stand-alone devices, but are coupled with mass spectrometry, gas chromatography or high-performance liquid chromatography in order to achieve a multi-dimensional separation, they come in various sizes, ranging from a few millimeters to several meters depending on the specific application, are capable of operating under a broad range of conditions. IMS instruments such as microscale high-field asymmetric waveform ion mobility spectrometry can be palm-portable for use in a range of applications including volatile organic compound monitoring, biological sample analysis, medical diagnosis and food quality monitoring.
Systems operated at higher pressure are accompanied by elevated temperature, while lower pressure systems do not require heating. IMS was first developed by Earl W. McDaniel of Georgia Institute of Technology in the 1950s and 1960s when he used drift cells with low applied electric fields to study gas phase ion mobilities and reactions. In the following decades, he coupled his new technique with a magnetic-sector mass spectrometer, with others utilizing his techniques in new ways. IMS cells have since been attached to many other mass spectrometers, gas chromatographs and high-performance liquid chromatography setups. IMS is a used technique, improvements and other uses are continually being developed. Ion mobility spectrometry's greatest strength is the speed at which separations occur—typically on the order of tens of milliseconds; this feature combined with its ease of use high sensitivity, compact design have allowed IMS as a commercial product to be used as a routine tool for the field detection of explosives and chemical weapons.
Major manufacturers of IMS screening devices used in airports are Smiths Detection. Smiths purchased Morpho Detection in 2017 and subsequently had to divest ownership of the Trace side of the business, sold on to Rapiscan Systems in mid 2017; the products are listed under ETD Itemisers. The latest model is a non radiation 4DX. In the pharmaceutical industry IMS is used in cleaning validations, demonstrating that reaction vessels are sufficiently clean to proceed with the next batch of pharmaceutical product. IMS is much faster and more accurate than HPLC and total organic carbon methods used. IMS is used for analyzing the composition of drugs produced, thereby finding a place in quality assurance and control; as a research tool ion mobility is becoming more used in the analysis of biological materials proteomics and metabolomics. For example, IMS-MS using MALDI as the ionization method has helped make advances in proteomics, providing faster high-resolution separations of protein pieces in analysis.
Moreover, it is a promising tool for glycomics, as rotationally averaged collision cross section values can be obtained. CCS values are important distinguishing characteristics of ions in the gas phase, in addition to the empirical determinations it can be calculated computationally when the 3D structure of the molecule is known; this way, adding CCS values of glycans and their fragments to databases will increase structural identification confidence and accuracy. Outside of laboratory purposes, IMS has found great usage as a detection tool for hazardous substances. More than 10,000 IMS devices are in use worldwide in airports, the US Army has more than 50,000 IMS devices. In industrial settings, uses of IMS include checking equipment cleanliness and detecting emission contents, such as determining the amount of hydrochloric and hydrofluoric acid in a stack gas from a process, it is applied in industrial purposes to detect harmful substances in air. In metabolomics the IMS is used to detect lung cancer, Chronic obstructive pulmonary disease, potential rejections after lung transplantation and relations to bacteria within the lung.
The physical quantity ion mobility K is defined as the proportionality factor between an ion's drift velocity vd in a gas and an electric field of strength E. v d = K E Ion mobilities are reported as reduced mobilities, correcting to standard gas density n0, which can be expressed in standard temperature T0 = 273 K and standard pressure p0 = 1013 hPa. It should be noted that this does not correct for other effects than the change in gas density and the reduced ion mobility is therefore still temperature dependent. K 0 = K n n 0 = K T 0 T p p 0 The ion mobility K can, under a variety of assumptions, be calculated by the Mason-Schamp equation. K = 3 16 2 π μ k T Q n σ where Q is the ion charge, n is the drift gas number density, μ is the reduced mass of the ion and the drift gas molec
The United States of America known as the United States or America, is a country composed of 50 states, a federal district, five major self-governing territories, various possessions. At 3.8 million square miles, the United States is the world's third or fourth largest country by total area and is smaller than the entire continent of Europe's 3.9 million square miles. With a population of over 327 million people, the U. S. is the third most populous country. The capital is Washington, D. C. and the largest city by population is New York City. Forty-eight states and the capital's federal district are contiguous in North America between Canada and Mexico; the State of Alaska is in the northwest corner of North America, bordered by Canada to the east and across the Bering Strait from Russia to the west. The State of Hawaii is an archipelago in the mid-Pacific Ocean; the U. S. territories are scattered about the Pacific Ocean and the Caribbean Sea, stretching across nine official time zones. The diverse geography and wildlife of the United States make it one of the world's 17 megadiverse countries.
Paleo-Indians migrated from Siberia to the North American mainland at least 12,000 years ago. European colonization began in the 16th century; the United States emerged from the thirteen British colonies established along the East Coast. Numerous disputes between Great Britain and the colonies following the French and Indian War led to the American Revolution, which began in 1775, the subsequent Declaration of Independence in 1776; the war ended in 1783 with the United States becoming the first country to gain independence from a European power. The current constitution was adopted in 1788, with the first ten amendments, collectively named the Bill of Rights, being ratified in 1791 to guarantee many fundamental civil liberties; the United States embarked on a vigorous expansion across North America throughout the 19th century, acquiring new territories, displacing Native American tribes, admitting new states until it spanned the continent by 1848. During the second half of the 19th century, the Civil War led to the abolition of slavery.
By the end of the century, the United States had extended into the Pacific Ocean, its economy, driven in large part by the Industrial Revolution, began to soar. The Spanish–American War and World War I confirmed the country's status as a global military power; the United States emerged from World War II as a global superpower, the first country to develop nuclear weapons, the only country to use them in warfare, a permanent member of the United Nations Security Council. Sweeping civil rights legislation, notably the Civil Rights Act of 1964, the Voting Rights Act of 1965 and the Fair Housing Act of 1968, outlawed discrimination based on race or color. During the Cold War, the United States and the Soviet Union competed in the Space Race, culminating with the 1969 U. S. Moon landing; the end of the Cold War and the collapse of the Soviet Union in 1991 left the United States as the world's sole superpower. The United States is the world's oldest surviving federation, it is a representative democracy.
The United States is a founding member of the United Nations, World Bank, International Monetary Fund, Organization of American States, other international organizations. The United States is a developed country, with the world's largest economy by nominal GDP and second-largest economy by PPP, accounting for a quarter of global GDP; the U. S. economy is post-industrial, characterized by the dominance of services and knowledge-based activities, although the manufacturing sector remains the second-largest in the world. The United States is the world's largest importer and the second largest exporter of goods, by value. Although its population is only 4.3% of the world total, the U. S. holds 31% of the total wealth in the world, the largest share of global wealth concentrated in a single country. Despite wide income and wealth disparities, the United States continues to rank high in measures of socioeconomic performance, including average wage, human development, per capita GDP, worker productivity.
The United States is the foremost military power in the world, making up a third of global military spending, is a leading political and scientific force internationally. In 1507, the German cartographer Martin Waldseemüller produced a world map on which he named the lands of the Western Hemisphere America in honor of the Italian explorer and cartographer Amerigo Vespucci; the first documentary evidence of the phrase "United States of America" is from a letter dated January 2, 1776, written by Stephen Moylan, Esq. to George Washington's aide-de-camp and Muster-Master General of the Continental Army, Lt. Col. Joseph Reed. Moylan expressed his wish to go "with full and ample powers from the United States of America to Spain" to seek assistance in the revolutionary war effort; the first known publication of the phrase "United States of America" was in an anonymous essay in The Virginia Gazette newspaper in Williamsburg, Virginia, on April 6, 1776. The second draft of the Articles of Confederation, prepared by John Dickinson and completed by June 17, 1776, at the latest, declared "The name of this Confederation shall be the'United States of America'".
The final version of the Articles sent to the states for ratification in late 1777 contains the sentence "The Stile of this Confederacy shall be'The United States of America'". In June 1776, Thomas Jefferson wrote the phrase "UNITED STATES OF AMERICA" in all capitalized letters in the headline of his "original Rough draught" of the Declaration of Independence; this draft of the document did not surface unti
Edward Uhler Condon was a distinguished American nuclear physicist, a pioneer in quantum mechanics, a participant in the development of radar and nuclear weapons during World War II as part of the Manhattan Project. The Franck–Condon principle and the Slater–Condon rules are co-named after him, he was the director of the National Bureau of Standards from 1945 to 1951. In 1946, Condon was president of the American Physical Society, in 1953 was president of the American Association for the Advancement of Science. During the McCarthy period, when efforts were being made to root out communist sympathizers in the United States, Edward Condon was a target of the House Un-American Activities Committee on the grounds that he was a'follower' of a'new revolutionary movement', quantum mechanics. Condon became known in 1968 as principal author of the Condon Report, an official review funded by the United States Air Force that concluded that unidentified flying objects have prosaic explanations; the lunar crater Condon is named for him.
Edward Uhler Condon was born on March 2, 1902, in Alamogordo, New Mexico, to William Edward Condon and Carolyn Uhler. His father was supervising the construction of a narrow-gauge railroad, many of which were built in the area by logging companies. After graduating from high school in Oakland, California in 1918, he worked as a journalist for three years at the Oakland Inquirer and other papers, he attended the University of California, Berkeley joining the College of Chemistry. Condon earned his bachelor's degree in his doctorate in two, his Ph. D. thesis combined work by Raymond Thayer Birge on measuring and analyzing band spectral intensities and a suggestion by James Franck. Thanks to a National Research Council fellowship, Condon studied at Göttingen under Max Born and at Munich under Arnold Sommerfeld. Under the latter, Condon rewrote his Ph. D. thesis using quantum mechanics, creating the Franck–Condon principle. After seeing an ad in Physical Review, Condon worked in public relations at Bell Telephone Laboratories in fall 1927, in particular promoting their discovery of electron diffraction.
Condon taught at Columbia University and was associate professor of physics at Princeton University from 1928 to 1937, except for a year at the University of Minnesota. With Philip M. Morse, he wrote Quantum Mechanics, the first English-language text on the subject in 1929. With G. H. Shortley, he wrote the Theory of Atomic Spectra, "a bible on the subject from the moment of its 1935 publication", he was associate director of research at the Westinghouse Electric Company in Pittsburgh, beginning in 1937, where he established research programs in nuclear physics, solid-state physics, mass spectroscopy. He headed the company's research on microwave radar development, he worked on the equipment used to isolate uranium for use in atomic bombs. He served as a consultant to the National Defense Research Committee during World War II and helped organize MIT's Radiation Laboratory. On May 11, 1940, Condon showcased. Condon filed for the patent on April 26, 1940 and got it on September 24, 1940 for his innovating machine, Nimatron.
In 1943, Condon joined the Manhattan Project. Within six weeks, he resigned as a result of conflicts about security with General Leslie R. Groves, the project's military leader. General Groves had objected when Condon's superior J. Robert Oppenheimer held a discussion with the director of the project's Metallurgical Lab at the University of Chicago. In his resignation letter, he explained: The thing which upsets me the most is the extraordinary close security policy.... I do not feel qualified to question the wisdom of this since I am unaware of the extent of enemy espionage and sabotage activities. I only want to say that in my case I found that the extreme concern with security was morbidly depressing--especially the discussion about censoring mail and telephone calls. From August 1943 to February 1945, Condon worked as a part-time consultant at Berkeley on the separation of U-235 and U-238. Condon was elected to the National Academy of Sciences in 1944. Following the war, Condon played a leading role in organizing scientists to lobby for civilian control of atomic energy rather than military control under strict security.
He worked as science adviser to Senator Brien McMahon, chairman of the Senate Special Committee on Atomic Energy, which wrote the McMahon-Douglas Act, enacted in August 1946, that created the Atomic Energy Commission, placing atomic energy under civilian control. Adopting an internationalist viewpoint, Condon favored international scientific cooperation and joined the American-Soviet Science Society. President Harry S. Truman nominated Condon to be director of the National Bureau of Standards in 1945, he was confirmed by the Senate without opposition and served until 1951. He was president of the American Physical Society in 1946. During the 1940s, Condon's security clearance status was questioned, re-established. On May 29, 1946, FBI Director J. Edgar Hoover wrote a letter intended for President Truman that named several senior government officials as part of a Soviet network, it described Condon as "nothing more or less than an espionage agent in disguise." The Truman administration ignored Hoover's charges.
On March 21, 1947, Truman signed United States Executive Order 9835 AKA the "Loyalty Order." Congressma
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 are interested in the root or ultimate causes of phenomena, frame their understanding in mathematical terms. Physicists work across a wide range of research fields, spanning all length scales: from sub-atomic and particle physics, through biological physics, to cosmological length scales encompassing the universe as a whole; the field includes two types of physicists: experimental physicists who specialize in the observation of physical phenomena and the analysis of experiments, theoretical physicists who specialize in mathematical modeling of physical systems to rationalize and predict natural phenomena. Physicists can apply their knowledge towards solving practical problems or to developing new technologies; the study and practice of physics is based on an intellectual ladder of discoveries and insights from ancient times to the present.
Many mathematical and physical ideas used today found their earliest expression in ancient Greek culture, for example in the work of Euclid, Thales of Miletus and Aristarchus. Roots emerged in ancient Asian culture and in the Islamic medieval period, for example the work of Alhazen in the 11th century; the modern scientific worldview and the bulk of physics education can be said to flow from the scientific revolution in Europe, starting with the work of Galileo Galilei and Johannes Kepler in the early 1600s. Newton's laws of motion and Newton's law of universal gravitation were formulated in the 17th century; the experimental discoveries of Faraday and the theory of Maxwell's equations of electromagnetism were developmental high points during the 19th century. Many physicists contributed to the development of quantum mechanics in the early-to-mid 20th century. New knowledge in the early 21st century includes a large increase in understanding physical cosmology; the broad and general study of nature, natural philosophy, was divided into several fields in the 19th century, when the concept of "science" received its modern shape.
Specific categories emerged, such as "biology" and "biologist", "physics" and "physicist", "chemistry" and "chemist", among other technical fields and titles. The term physicist was coined by William Whewell in his 1840 book The Philosophy of the Inductive Sciences. A standard undergraduate physics curriculum consists of classical mechanics and magnetism, non-relativistic quantum mechanics, statistical mechanics and thermodynamics, laboratory experience. Physics students need training in mathematics, in computer science. Any physics-oriented career position requires at least an undergraduate degree in physics or applied physics, while career options widen with a Master's degree like MSc, MPhil, MPhys or MSci. For research-oriented careers, students work toward a doctoral degree specializing in a particular field. Fields of specialization include experimental and theoretical astrophysics, atomic physics, biological physics, chemical physics, condensed matter physics, geophysics, gravitational physics, material science, medical physics, molecular physics, nuclear physics, radiophysics, electromagnetic field and microwave physics, particle physics, plasma physics.
The highest honor awarded to physicists is the Nobel Prize in Physics, awarded since 1901 by the Royal Swedish Academy of Sciences. National physics professional societies have many awards for professional recognition. In the case of the American Physical Society, as of 2017, there are 33 separate prizes and 38 separate awards in the field; the three major employers of career physicists are academic institutions and private industries, with the largest employer being the last. Physicists in academia or government labs tend to have titles such as Assistants, Professors, Sr./Jr. Scientist, or postdocs; as per the American Institute of Physics, some 20% of new physics Ph. D.s holds jobs in engineering development programs, while 14% turn to computer software and about 11% are in business/education. A majority of physicists employed apply their skills and training to interdisciplinary sectors. Job titles for graduate physicists include Agricultural Scientist, Air Traffic Controller, Computer Programmer, Electrical Engineer, Environmental Analyst, Medical Physicist, Oceanographer, Physics Teacher/Professor/Researcher, Research Scientist, Reactor Physicist, Engineering Physicist, Satellite Missions Analyst, Science Writer, Software Engineer, Systems Engineer, Microelectronics Engineer, Radar Developer, Technical Consultant, etc.
A majority of Physics terminal bachelor's degree holders are employed in the private sector. Other fields are academia and military service, nonprofit entities and teaching. Typical duties of physicists with master's and doctoral degrees working in their domain involve research and analysis, data preparation, instrumentation and development of industrial or medical equipment and software development, etc. Chartered Physicist is a chartered status and a professional qualification awarded by the Institute of Physics, it is denoted by the postnominals "CPhys". Achieving chartered status in any profession denotes to the wider community a high level of specialised subject knowledge and professional competence. According to the Institute of Physics, holders of the award of the Chartered Physicist demonst
Carl Barus was an American physicist and the maternal great-uncle of the American novelist Kurt Vonnegut. Barus was born in United States; the son of German immigrants graduated from Woodward High School, together with William Howard Taft, in 1874. After studying mining engineering for two years, he moved to Würzburg, where he studied physics under Friedrich Kohlrausch, graduated summa cum laude in 1879. Barus married Annie Gertrude Howes on January 20, 1887, they had two children and Deborah. In the United States in 1892, he was a member of the American Philosophical Society, the youngest of all members to National Academy of Sciences. In 1903 he was appointed as a dean of the Brown University Graduate Department, which he was controlling from his office in Wilson Hall, he remained the dean of the graduate school until his retirement in 1926. By that time, the department had grown large enough to become a school within the university, attributed to his many contributions. In 1905 he was a corresponding member of Britain and the same year became a member of the First International Congress of Radiology and Electricity at Brussels.
The same year, he became a member of the Physikalisch-Medizinische Sozietät at Erlangen. The same year he became the fourth president of American Physical Society, in 1906, became a member on the advisory board of physics, at the Carnegie Institution of Washington state. Barus died in Rhode Island, United States. Biographical Memoir of Carl Barus 1856-1935 by Robert Bruce Lindsay, presented to the National Academy of Sciences at the Autumn meeting. Biography from Brown University Works by or about Carl Barus at Internet ArchiveSmithsonian Institution ArchivesCarl Barus Carl Barus Papers, 1891, 1893
Electrospinning is a fiber production method which uses electric force to draw charged threads of polymer solutions or polymer melts up to fiber diameters in the order of some hundred nanometers. Electrospinning shares characteristics of both electrospraying and conventional solution dry spinning of fibers; the process does not require the use of coagulation chemistry or high temperatures to produce solid threads from solution. This makes the process suited to the production of fibers using large and complex molecules. Electrospinning from molten precursors is practiced; when a sufficiently high voltage is applied to a liquid droplet, the body of the liquid becomes charged, electrostatic repulsion counteracts the surface tension and the droplet is stretched. This point of eruption is known as the Taylor cone. If the molecular cohesion of the liquid is sufficiently high, stream breakup does not occur and a charged liquid jet is formed; as the jet dries in flight, the mode of current flow changes from ohmic to convective as the charge migrates to the surface of the fiber.
The jet is elongated by a whipping process caused by electrostatic repulsion initiated at small bends in the fiber, until it is deposited on the grounded collector. The elongation and thinning of the fiber resulting from this bending instability leads to the formation of uniform fibers with nanometer-scale diameters. Molecular weight, molecular-weight distribution and architecture of the polymer Solution properties Electric potential, flow rate and concentration Distance between the capillary and collection screen Ambient parameters Motion and size of target screen Needle gauge The standard laboratory setup for electrospinning consists of a spinneret connected to a high-voltage direct current power supply, a syringe pump, a grounded collector. A polymer solution, sol-gel, particulate suspension or melt is loaded into the syringe and this liquid is extruded from the needle tip at a constant rate by a syringe pump. Alternatively, the droplet at the tip of the spinneret can be replenished by feeding from a header tank providing a constant feed pressure.
This constant pressure type feed works better for lower viscosity feedstocks. Multiplying the needles Rotating roller electrospinning Wire electrospinning Bubble electrospinning Ball electrospinning High speed electrospinning Plate edge electrospinning Bowl electrospinning Hollow tube electrospinning Rotary cone electrospinning Spiral coil electrospinning Electroblowing Needleless electrospinning Alternating current electrospinning Modification of the spinneret and/or the type of solution can allow for the creation of fibers with unique structures and properties. Electrospun fibers can adopt a porous or core–shell morphology depending on the type of materials being spun as well as the evaporation rates and miscibility for the solvents involved. For techniques which involve multiple spinning fluids, the general criteria for the creation of fibers depends upon the spinnability of the outer solution; this opens up the possibility of creating composite fibers which can function as drug delivery systems or possess the ability to self-heal upon failure.
A coaxial setup uses a dual-solution feed system which allows for the injection of one solution into another at the tip of the spinneret. The sheath fluid is believed to act as a carrier which draws in the inner fluid at the Taylor Cone of the electrospinning jet. If the solutions are immiscible a core shell structure is observed. Miscible solutions however can result in porosity or a fiber with distinct phases due to phase separation during solidification of the fiber. For more advanced setups, a triaxial or quadaxial spinneret can be used with multiple solutions. Emulsions can be used to create core shell or composite fibers without modification of the spinneret. However, these fibers are more difficult to produce as compared to coaxial spinning due to the greater number of variables which must be accounted for in creating the emulsion. A water phase and an immiscible solvent phase are mixed in the presence of an emulsifying agent to form the emulsion. Any agent which stabilizes the interface between the immiscible phases can be used.
Surfactants such as sodium dodecyl sulfate and nanoparticles have been used successfully. During the electrospinning process the emulsion droplets within the fluid are stretched and confined leading to their coalescence. If the volume fraction of inner fluid is sufficiently high, a continuous inner core can be formed. Electrospinning of blends is a variation of this technique which uses the fact that polymers are immiscible with each and can phase segregate without the use of surfactants; this method can be simplified further. Electrospinning of polymer melts eliminates the need for volatile solvents in solution electrospinning. Semi crystalline polymer fibers such as PE, PET and PP, which would otherwise be impossible or difficult to create using solution spinning, can be created; the setup is similar to that employed in conventional electrospinning and includes the use of a syringe or spinneret, a high voltage supply and the collector. The polymer melt is produced by heating from either resistance heating, circulating fluids, air heating or lasers.
Due to the high viscosity of polymer melts, the fiber diameters are slightly larger than those obtained f
John Hasbrouck Van Vleck
John Hasbrouck Van Vleck was an American physicist and mathematician. He was co-awarded the Nobel Prize in Physics in 1977, for his contributions to the understanding of the behavior of electrons in magnetic solids. Born in Middletown, the son of mathematician Edward Burr Van Vleck and grandson of astronomer John Monroe Van Vleck, he grew up in Madison and received an A. B. degree from the University of Wisconsin–Madison in 1920. He went to Harvard for graduate studies and earned a Ph. D degree in 1922, he joined the University of Minnesota as an assistant professor in 1923 moved to the University of Wisconsin–Madison before settling at Harvard. He earned Honorary D. Sc. or D. Honoris Causa, degree from Wesleyan University in 1936. J. H. Van Vleck established the fundamentals of the quantum mechanical theory of magnetism and the crystal field theory, he is regarded as the Father of Modern Magnetism. During World War II, J. H. Van Vleck worked on radar at the MIT Radiation Lab, he was half time on the staff at Harvard.
He showed that at about 1.25-centimeter wavelength water molecules in the atmosphere would lead to troublesome absorption and that at 0.5-centimeter wavelength there would be a similar absorption by oxygen molecules. This was to have important consequences not just for military radar systems but for the new science of radioastronomy. J. H. Van Vleck participated in the Manhattan Project. In June 1942, J. Robert Oppenheimer held a summer study for confirming the concept and feasibility of a nuclear weapon at the University of California, Berkeley. Eight theoretical scientists, including J. H. Van Vleck, attended it. From July to September, the theoretical study group examined and developed the principles of atomic bomb design. J. H. Van Vleck's theoretical work led to the establishment of the Los Alamos Nuclear Weapons Laboratory, he served on the Los Alamos Review committee in 1943. The committee, established by General Leslie Groves consisted of W. K. Lewis of MIT, Chairman. Tolman, Vice Chairman of NDRC.
The committee's important contribution was a reduction in the size of the firing gun for the Little Boy atomic bomb, a concept that eliminated additional design weight and sped up production of the bomb for its eventual release over Hiroshima. However, it was not employed for the Fat Man bomb at Nagasaki, which relied on implosion of a plutonium shell to reach critical mass. In 1961/62 he was George Eastman Visiting Professor at University of Oxford and held a professorship at Balliol College. In 1950 he became foreign member of the Royal Netherlands Academy of Sciences, he was awarded the National Medal of Science in 1966 and the Lorentz Medal in 1974. For his contributions to the understanding of the behavior of electrons in magnetic solids, Van Vleck was awarded the Nobel Prize in Physics 1977, along with Philip W. Anderson and Sir Nevill Mott. Van Vleck transformations, Van Vleck paramagnetism and Van Vleck formula are named after him. Van Vleck died in Cambridge, aged 81; the Absorption of Radiation by Multiply Periodic Orbits, its Relation to the Correspondence Principle and the Rayleigh–Jeans Law.
Part I. Some Extensions of the Correspondence Principle, Physical Review, vol. 24, Issue 4, pp. 330–346 The Absorption of Radiation by Multiply Periodic Orbits, its Relation to the Correspondence Principle and the Rayleigh–Jeans Law. Part II. Calculation of Absorption by Multiply Periodic Orbits, Physical Review, vol. 24, Issue 4, pp. 347–365 Quantum Principles and Line Spectra, The Theory of Electric and Magnetic Susceptibilities. Quantum Mechanics, The Key to Understanding Magnetism, Nobel Lecture, December 8, 1977 The Correspondence Principle in the Statistical Interpretation of Quantum Mechanics Proceedings of the National Academy of Sciences of USA, vol. 14, pp. 178–188 He was awarded the Irving Langmuir Award in 1965, the National Medal of Science in 1966 and elected a Foreign Member of the Royal Society in 1967. He was awarded the Elliott Cresson Medal in 1971, the Lorentz Medal in 1974 and the Nobel Prize in Physics in 1977. J. H. Van Vleck and his wife Abigail were important art collectors in the medium of Japanese woodblock prints, known as Van Vleck Collection.
It was inherited from his father Edward Burr Van Vleck. They donated it to the Chazen Museum of Art in Wisconsin in 1980s; the Theory of Electric and Magnetic Susceptibilities John Hasbrouck van Vleck NNDB Duncan and Janssen, Michel. "On the verge of Undeutung in Minnesota: Van Vleck and the correspondence principle. Part one," Archive for History of Exact Sciences 2007, 61:6, pages 553–624. Chazen Museum of Art Oral history interview transcript with John Hasbrouck Van Vleck 14 October 1963, American Institute of Physics, Niels Bohr Library & Archives Oral history interview transcript with John Hasbrouck Van Vleck 28 February 1966, American Institute of Physics, Niels Bohr Library & Archives Oral history interview transcript with John Hasbrouck Van Vleck 28 January 1977, American Institute of Physics, Niels Bohr Library & Archives