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Hydrogen Isocyanide
Hydrogen isocyanide is a chemical with the molecular formula HNC. It is a minor tautomer of hydrogen cyanide (HCN). Its importance in the field of astrochemistry is linked to its ubiquity in the interstellar medium. Nomenclature Both ''hydrogen isocyanide'' and ''azanylidyniummethanide'' are correct IUPAC names for HNC. There is no preferred IUPAC name. The second one is according to the '' substitutive nomenclature rules'', derived from the '' parent hydride'' azane () and the anion methanide (). Molecular properties Hydrogen isocyanide (HNC) is a linear triatomic molecule with C∞v point group symmetry. It is a zwitterion and an isomer of hydrogen cyanide (HCN). Both HNC and HCN have large, similar dipole moments, with ''μ''HNC = 3.05 Debye and ''μ''HCN = 2.98 Debye respectively. These large dipole moments facilitate the easy observation of these species in the interstellar medium. HNC−HCN tautomerism As HNC is higher in energy than HCN by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrocyanonium
HCNH+, also known as protonated hydrogen cyanide, is a molecular ion of astrophysical interest. It also exists in the condensed state when formed by superacids. Structure In the ground state, HCH is a simple linear molecule, whereas its excited triplet state is expected to have ''cis'' and ''trans'' isomeric forms. The higher-energy structural isomers H2CN+ and CH2 have also been studied theoretically. Laboratory studies As a relatively simple molecular ion, HCNH+ has been extensively studied in the laboratory. The very first spectrum taken at any wavelength focused on the ''ν''2 (C−H stretch) ro-vibrational band in the infrared. Soon afterward, the same authors reported on their investigation of the ''ν''1 (N−H stretch) band. Following these initial studies, several groups published manuscripts on the various ro-vibrational spectra of HCNH+, including studies of the ''ν''3 band (C≡N stretch), the ''ν''4 band (H−C≡N bend), and the ''ν''5 band (H−N≡C bend) . ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Debye
The debye ( , ; symbol: D) is a CGS unit (a non- SI metric unit) of electric dipole momentTwo equal and opposite charges separated by some distance constitute an electric dipole. This dipole possesses an electric dipole moment whose value is given as charge times length of separation. The dipole itself is a vector whose direction coincides with the position vector of the positive charge with respect to the negative charge: : p = ''q''r. named in honour of the physicist Peter J. W. Debye. It is defined as statcoulomb-centimetres.The statcoulomb is also known as the franklin or electrostatic unit of charge. : 1 statC = 1 Fr = 1 esu = 1 cm3/2⋅g1/2⋅s−1. Historically the debye was defined as the dipole moment resulting from two charges of opposite sign but an equal magnitude of 10−10 statcoulomb10−10 statcoulomb corresponds to approximately 0.2083 units of elementary charge. (generally called e.s.u. (electrostatic unit) in ol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Cyanide
Hydrogen cyanide (formerly known as prussic acid) is a chemical compound with the chemical formula, formula HCN and structural formula . It is a highly toxic and flammable liquid that boiling, boils slightly above room temperature, at . HCN is produced on an industrial scale and is a highly valued Precursor (chemistry), precursor to many chemical compounds ranging from polymers to pharmaceuticals. Large-scale applications are for the production of potassium cyanide and adiponitrile, used in mining and plastics, respectively. It is more toxic than solid cyanide compounds due to its Volatility (chemistry), volatile nature. A solution of hydrogen cyanide in water (molecule), water, represented as HCN(aqueous, aq), is called ''hydrocyanic acid''. The Salt (chemistry), salts of the cyanide anion are known as cyanides. Whether hydrogen cyanide is an organic compound or not is a topic of debate among chemists, and opinions vary from author to author. Traditionally, it is considered ino ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atacama Large Millimeter Array
The Atacama Large Millimeter/submillimeter Array (ALMA) is an astronomical interferometer of 66 radio telescopes in the Atacama Desert of northern Chile, which observe electromagnetic radiation at millimeter and submillimeter wavelengths. The array has been constructed on the elevation Chajnantor plateau – near the Llano de Chajnantor Observatory and the Atacama Pathfinder Experiment. This location was chosen for its high elevation and low humidity, factors which are crucial to reduce noise and decrease signal attenuation due to Earth's atmosphere. ALMA provides insight on star birth during the early Stelliferous era and detailed imaging of local star and planet formation. ALMA is an international partnership amongst Europe, the United States, Canada, Japan, South Korea, Taiwan, and Chile. Costing about US$1.4 billion, it is the most expensive ground-based telescope in operation. ALMA began scientific observations in the second half of 2011 and the first images were rel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectroscopy
Spectroscopy is the field of study that measures and interprets electromagnetic spectra. In narrower contexts, spectroscopy is the precise study of color as generalized from visible light to all bands of the electromagnetic spectrum. Spectroscopy, primarily in the electromagnetic spectrum, is a fundamental exploratory tool in the fields of astronomy, chemistry, materials science, and physics, allowing the composition, physical structure and electronic structure of matter to be investigated at the atomic, molecular and macro scale, and over astronomical distances. Historically, spectroscopy originated as the study of the wavelength dependence of the absorption by gas phase matter of visible light dispersed by a prism. Current applications of spectroscopy include biomedical spectroscopy in the areas of tissue analysis and medical imaging. Matter waves and acoustic waves can also be considered forms of radiative energy, and recently gravitational waves have been associa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Veleta (Sierra Nevada)
Veleta (from the Arab word "Balata", meaning cliff) or Pico del Veleta is the third highest peak of the Iberian Peninsula and the second highest of the Sierra Nevada. Its height is given variously as , and . The mountain can be seen from the city of Granada. Veleta's northern slopes are home to the Sierra Nevada Ski Station. The access road that takes one to approximately 10 metres below the summit is the highest paved road in Europe across the mountains from Granada to the western Alpujarras. This road was built before the creation of the Sierra Nevada National Park in 1999. It has since been closed to general traffic beyond Hoya de la Mora, just above the ski station. However, the road is still used by ski station employees, national park rangers, observatory staff, cyclists and walkers, and by a microbus service which takes hikers up to Posiciones del Veleta, a viewpoint 3,100 metres above sea level. In summer it is a relatively easy walk up to the summit from there. The C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IRAM 30-m
The IRAM 30m telescope is a radio telescope, located in the Sierra Nevada Mountain Range, Spain. It is operated by the Institute for Radio Astronomy in the Millimetre Range (IRAM) for observing astronomical objects in the millimetre range of the electromagnetic spectrum. With its large surface and wide-angle camera, the telescope is capable of exploring vast cosmic objects. It is one of the largest and most sensitive millimetre wavelength telescopes in the world, serving over 200 astronomers annually. The telescope is primarily used to study interstellar clouds, star nurseries, galaxies, and black hole jets. Together with IRAM's other facility, the NOEMA observatory, the telescope is part of the global Event Horizon Telescope array. It was the only station in Europe to participate in the 2017 EHT observing campaign that produced the first image of a black hole. Operation Built from 1980 to 1984, the telescope operates at 2850 meters above sea level. Due to its large sur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trihydrogen Cation
The trihydrogen cation or protonated molecular hydrogen ( IUPAC name: hydrogen onium ion) is a cation (positive ion) with formula , consisting of three hydrogen nuclei (protons) sharing two electrons. The trihydrogen cation is one of the most abundant ions in the universe. It is stable in the interstellar medium (ISM) due to the low temperature and low density of interstellar space. The role that plays in the gas-phase chemistry of the ISM is unparalleled by any other polyatomic ion. The trihydrogen cation is the simplest triatomic molecule, because its two electrons are the only valence electrons in the system. It is also the simplest example of a three-center two-electron bond system. History was first discovered by J. J. Thomson in 1911. While using an early form of mass spectrometry to study the resultant species of plasma discharges, he discovered a large abundance of a polyatomic ion with a mass-to-charge ratio of 3. He stated that the only two possibilities were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dissociative Recombination
Dissociative recombination is a chemical process in which a positive polyatomic ion recombines with an electron, and as a result, the neutral molecule dissociates. This reaction is important for interstellar and atmospheric chemistry. On Earth, dissociative recombination rarely occurs naturally, as free electrons react with any molecule (even neutral molecules) they encounter. Even in the best laboratory conditions, dissociative recombination is hard to observe, but it is an important reaction in systems which have large populations of ionized molecules such as atmospheric-pressure plasmas. In astrophysics, dissociative recombination is one of the main mechanisms by which molecules are broken down, and other molecules are formed. The existence of dissociative recombination is possible due to the vacuum of the interstellar medium. A typical example of dissociative recombination in astrophysics is: : See also *Astrochemistry *Ionization Ionization or ionisation is the proces ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photodissociation Region
In astrophysics, photodissociation regions (or photon-dominated regions, PDRs) are predominantly neutral regions of the interstellar medium in which far ultraviolet photons strongly influence the gas chemistry and act as the most important source of heat. They constitute a sort of shell around sources of far-UV photons at a distance where the interstellar gas is dense enough, and the flux from the photon source is no longer strong enough, to strip electrons from the neutral constituent atoms. Despite being composed of denser gas, PDRs still have too low a column density to prevent the penetration of far-UV photons from distant, massive stars. PDRs are also composed of a cold molecular zone that has the potential for star formation. They achieve this cooling by far-infrared fine line emissions of neutral oxygen and ionized carbon. It is theorized that PDRs are able to maintain their shape by trapped magnetic fields originating from the far-UV source. A typical and well-studied examp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Hole
A black hole is a massive, compact astronomical object so dense that its gravity prevents anything from escaping, even light. Albert Einstein's theory of general relativity predicts that a sufficiently compact mass will form a black hole. The boundary (topology), boundary of no escape is called the event horizon. A black hole has a great effect on the fate and circumstances of an object crossing it, but has no locally detectable features according to general relativity. In many ways, a black hole acts like an ideal black body, as it reflects no light. Quantum field theory in curved spacetime predicts that event horizons emit Hawking radiation, with thermal radiation, the same spectrum as a black body of a temperature inversely proportional to its mass. This temperature is of the Orders of magnitude (temperature), order of billionths of a kelvin for stellar black holes, making it essentially impossible to observe directly. Objects whose gravitational fields are too strong for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Star Formation
Star formation is the process by which dense regions within molecular clouds in interstellar space—sometimes referred to as "stellar nurseries" or "star-forming regions"—Jeans instability, collapse and form stars. As a branch of astronomy, star formation includes the study of the interstellar medium (ISM) and giant molecular clouds (GMC) as precursors to the star formation process, and the study of protostars and young stellar objects as its immediate products. It is closely related to planet formation, another branch of astronomy. Star formation theory, as well as accounting for the formation of a single star, must also account for the statistics of binary stars and the initial mass function. Most stars do not form in isolation but as part of a group of stars referred as star clusters or stellar associations. First stars Star formation is divided into three groups called "Populations". Population III stars formed from primordial hydrogen after the Big Bang. These stars are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
