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Pentacene 200
Pentacene () is a polycyclic aromatic hydrocarbon consisting of five linearly-fused benzene () rings. This highly conjugated compound is an organic semiconductor. The compound generates excitons upon absorption of ultra-violet ( UV) or visible light; this makes it very sensitive to oxidation. For this reason, this compound, which is a purple powder, slowly degrades upon exposure to air and light. Structurally, pentacene is one of the linear acenes, the previous one being tetracene (four fused benzene rings) and the next one being hexacene (six fused benzene rings). In August 2009, a group of researchers from IBM published experimental results of imaging a single molecule of pentacene using an atomic force microscope. In July 2011, they used a modification of scanning tunneling microscopy to experimentally determine the shapes of the highest occupied and lowest unoccupied molecular orbitals. In 2012, pentacene-doped ''p''-terphenyl was shown to be effective as the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triclinic
180px, Triclinic (a ≠ b ≠ c and α ≠ β ≠ γ ) In crystallography, the triclinic (or anorthic) crystal system is one of the 7 crystal systems. A crystal system is described by three basis vectors. In the triclinic system, the crystal is described by vectors of unequal length, as in the orthorhombic system. In addition, the angles between these vectors must all be different and may not include 90°. The triclinic lattice is the least symmetric of the 14 three-dimensional Bravais lattices. It has (itself) the minimum symmetry all lattices have: points of inversion at each lattice point and at 7 more points for each lattice point: at the midpoints of the edges and the faces, and at the center points. It is the only lattice type that itself has no mirror planes. Crystal classes The triclinic crystal system class names, examples, Schönflies notation, Hermann-Mauguin notation, point groups, International Tables for Crystallography space group number, orbifold, type, and sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scanning Tunneling Microscopy
A scanning tunneling microscope (STM) is a type of microscope used for imaging surfaces at the atomic level. Its development in 1981 earned its inventors, Gerd Binnig and Heinrich Rohrer, then at IBM Zürich, the Nobel Prize in Physics in 1986. STM senses the surface by using an extremely sharp conducting tip that can distinguish features smaller than 0.1 nm with a 0.01 nm (10 pm) depth resolution. This means that individual atoms can routinely be imaged and manipulated. Most microscopes are built for use in ultra-high vacuum at temperatures approaching zero kelvin, but variants exist for studies in air, water and other environments, and for temperatures over 1000 °C. STM is based on the concept of quantum tunneling. When the tip is brought very near to the surface to be examined, a bias voltage applied between the two allows electrons to tunnel through the vacuum separating them. The resulting ''tunneling current'' is a function of the tip position, applied ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Georg Thieme Verlag
Thieme Medical Publishers is a German medical and science publisher in the Thieme Publishing Group. It produces professional journals, textbooks, atlases, monographs and reference books in both German and English covering a variety of medical specialties, including neurosurgery, orthopaedics, endocrinology, urology, radiology, anatomy, chemistry, otolaryngology, ophthalmology, audiology and speech-language pathology, complementary and alternative medicine. Thieme has more than 1,000 employees and maintains offices in seven cities worldwide, including New York City, Beijing, Delhi, Stuttgart, and three other cities in Germany. History Georg Thieme Verlag was founded in 1886 in Leipzig, Germany, by Georg Thieme when he was 26 years old. Thieme remains privately held and family-owned. The company received some early success in 1896 by publishing Wilhelm Röntgen's famous picture of his wife's hand in what is still one of Thieme's and Germany's oldest journals, the ''Deutsche ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elbs Reaction
The Elbs reaction is an organic reaction describing the pyrolysis of an ortho methyl substituted benzophenone to a condensed polyaromatic. The reaction is named after its inventor, the German chemist Karl Elbs, also responsible for the Elbs oxidation. The reaction was published in 1884.Karl Elbs, Einar Larsen. (1884). "Ueber Paraxylylphenylketon." ''Ber. Dtsch. Chem. Ges.'' (in German), 17(2): 2847–2849, . K. Elbs. (1886) "Beiträge zur Kenntniss aromatischer Ketone. Erste Mittheilung." '' J. Prakt. Chem.'' (in German), 33(1): 180–188, . Elbs however did not correctly interpret the reaction product due to a lack of knowledge about naphthalene structure. Scope The Elbs reaction enables the synthesis of condensed aromatic systems. As already demonstrated by Elbs in 1884 it is possible to obtain anthracene through dehydration. Larger aromatic systems like pentacene are also feasible. This reaction does not take place in a single step but leads first to dihydropentacene that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mildred May Gostling
Mildred May Gostling (15 December 1873 – 19 February 1962), also published under her married name Mildred Mills, was an English chemist who completed research in carbohydrate chemistry. She was one of the nineteen signatories on a letter from professional female chemists to the Chemical Society (later the Royal Society of Chemistry) requesting that women be accepted as Fellows to the Society. Biography Gostling was the daughter of George and Sarah Gostling and was born in Stowmarket, Suffolk, in 1873, and lived on Ipswich Street, Stowmarket. Her father was a pharmaceutical chemist and dental surgeon. She attended the Royal Holloway College from 1893 to 1897, obtaining a BSc in Chemistry. She was most likely taught there by Elizabeth Eleanor Field. After graduating from Royal Holloway with a BSc (First Class), she was awarded a Bathurst Studentship, which were founded in 1882 for the encouragement of advanced work in any of the natural sciences at Newnham College, Cambridge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William Hobson Mills
William Hobson Mills FRS (6 July 1873 – 22 February 1959) was a British organic chemist. Biography William Hobson Mills was born in Hammersmith on 6 July 1873, the eldest of five children of William Henry Mills, an architect, and Emily Wiles Quincey (née Hobson). The family moved that autumn to Emily's home town, Spalding, Lincolnshire. Mills was educated at Spalding Grammar School and then at Uppingham School. He entered Jesus College, Cambridge in October 1892 and read natural sciences. An injury to his Achilles tendon – sustained at Uppingham – meant that he remained at home for the academic year 1893–1894. He returned to Cambridge in October 1894, and obtained a First Class in the Natural Sciences Tripos, Part I, in 1896, and in Part II (Chemistry) in 1897. Mills began research in the Cambridge University Chemical Laboratory under the New Zealand chemist Thomas Easterfield. He was encouraged to work on the conversion of 2,4-dibenzoylmesitylene to a pentacyclic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentacene
Pentacene () is a polycyclic aromatic hydrocarbon consisting of five linearly-fused benzene () rings. This highly conjugated compound is an organic semiconductor. The compound generates excitons upon absorption of ultra-violet ( UV) or visible light; this makes it very sensitive to oxidation. For this reason, this compound, which is a purple powder, slowly degrades upon exposure to air and light. Structurally, pentacene is one of the linear acenes, the previous one being tetracene (four fused benzene rings) and the next one being hexacene (six fused benzene rings). In August 2009, a group of researchers from IBM published experimental results of imaging a single molecule of pentacene using an atomic force microscope. In July 2011, they used a modification of scanning tunneling microscopy to experimentally determine the shapes of the highest occupied and lowest unoccupied molecular orbitals. In 2012, pentacene-doped ''p''-terphenyl was shown to be effective as the amplifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentacene On Ni(111) STM
Pentacene () is a polycyclic aromatic hydrocarbon consisting of five linearly-fused benzene () rings. This highly conjugated compound is an organic semiconductor. The compound generates excitons upon absorption of ultra-violet ( UV) or visible light; this makes it very sensitive to oxidation. For this reason, this compound, which is a purple powder, slowly degrades upon exposure to air and light. Structurally, pentacene is one of the linear acenes, the previous one being tetracene (four fused benzene rings) and the next one being hexacene (six fused benzene rings). In August 2009, a group of researchers from IBM published experimental results of imaging a single molecule of pentacene using an atomic force microscope. In July 2011, they used a modification of scanning tunneling microscopy to experimentally determine the shapes of the highest occupied and lowest unoccupied molecular orbitals. In 2012, pentacene-doped ''p''-terphenyl was shown to be effective as the amplifier ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nature (journal)
''Nature'' is a British weekly scientific journal founded and based in London, England. As a multidisciplinary publication, ''Nature'' features peer-reviewed research from a variety of academic disciplines, mainly in science and technology. It has core editorial offices across the United States, continental Europe, and Asia under the international scientific publishing company Springer Nature. ''Nature'' was one of the world's most cited scientific journals by the Science Edition of the 2019 ''Journal Citation Reports'' (with an ascribed impact factor of 42.778), making it one of the world's most-read and most prestigious academic journals. , it claimed an online readership of about three million unique readers per month. Founded in autumn 1869, ''Nature'' was first circulated by Norman Lockyer and Alexander Macmillan as a public forum for scientific innovations. The mid-20th century facilitated an editorial expansion for the journal; ''Nature'' redoubled its efforts in exp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maser
A maser (, an acronym for microwave amplification by stimulated emission of radiation) is a device that produces coherent electromagnetic waves through amplification by stimulated emission. The first maser was built by Charles H. Townes, James P. Gordon, and Herbert J. Zeiger at Columbia University in 1953. Townes, Nikolay Basov and Alexander Prokhorov were awarded the 1964 Nobel Prize in Physics for theoretical work leading to the maser. Masers are also used as the timekeeping device in atomic clocks, and as extremely low-noise microwave amplifiers in radio telescopes and deep-space spacecraft communication ground stations. Modern masers can be designed to generate electromagnetic waves at not only microwave frequencies but also radio and infrared frequencies. For this reason, Townes suggested replacing ''microwave'' with the word ''molecular'' as the first word in the acronym ''maser''. The laser works by the same principle as the maser but produces higher frequency ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
P-terphenyl
Terphenyls are a group of closely related aromatic hydrocarbons. Also known as diphenylbenzenes or triphenyls, they consist of a central benzene ring substituted with two phenyl groups. There are three substitution patterns: ''ortho''-terphenyl, ''meta''-terphenyl, and ''para''-terphenyl. Commercial grade terphenyl is generally a mixture of the three isomers. This mixture is used in the production of polychlorinated terphenyls, which were formerly used as heat storage and transfer agents.2C4H2S. It is an oligomer of the heterocycle thiophene, a shorter oligomer is dithienyl, and the parent polymer is polythiophene. In the most common isomer of terthiophene, two thien ... References {{reflist External links p-Terphenylat the Oregon Laser Medical Center at Centers f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phys
Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which relates to the order of nature, or, in other words, to the regular succession of events." Physics is one of the most fundamental scientific disciplines, with its main goal being to understand how the universe behaves. "Physics is one of the most fundamental of the sciences. Scientists of all disciplines use the ideas of physics, including chemists who study the structure of molecules, paleontologists who try to reconstruct how dinosaurs walked, and climatologists who study how human activities affect the atmosphere and oceans. Physics is also the foundation of all engineering and technology. No engineer could design a flat-screen TV, an interplanetary spacecraft, or even a better mousetrap without first understanding the basic laws of physics. (. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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