1.
Phosphorescent (band)
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Phosphorescent is the working moniker of American singer-songwriter, Matthew Houck. Originally from Alabama, Houck began recording and performing under this nom de plume in 2001 in Athens and he is currently based in Brooklyn, New York. Before recording under the name Phosphorescent, Matthew Houck traveled the world playing under the moniker Fillup Shack, Houck later changed his recording name to Phosphorescent, and released the full-length LP A Hundred Times or More in 2003. Notably, in the notes of A Hundred Times or More. The album was released through Athens-based independent label Warm Records, the following year, he released the EP The Weight of Flight. Phosphorescent rose to critical acclaim after releasing Aw Come Aw Wry in August 2005. The latter was named the 12th best album of 2007 by Stylus Magazine, in 2009, inspired by Willie Nelsons tribute album to Lefty Frizzell To Lefty From Willie, Houck crafted a tribute album to Nelson himself entitled, To Willie which was released through Dead Oceans. Phosphorescent released Heres to Taking It Easy in 2010, muchacho, Phosphorescents sixth studio album was released in 2013 to critical acclaim. The song Wolves from 2007s Pride was used in the 2011 film Margin Call, starring Kevin Spacey, the song Nothing Was Stolen from 2010s Heres to Taking It Easy was used in the 2012 film The Vow, starring Rachel McAdams and Channing Tatum. It is also used in season 1 episode 2 Signal and Noise of the television series Frequency, official website Ukulele Session by Noahm for Le Soir Phosphorescent, A Full-Grown Man
2.
Bioluminescence
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Bioluminescence is the production and emission of light by a living organism. It is a form of chemiluminescence, Bioluminescence occurs widely in marine vertebrates and invertebrates, as well as in some fungi, microorganisms including some bioluminescent bacteria and terrestrial invertebrates such as fireflies. In some animals, the light is produced by organisms such as Vibrio bacteria. The principal chemical reaction in bioluminescence involves the light-emitting pigment luciferin, the enzyme catalyzes the oxidation of luciferin. In some species, the type of luciferin requires cofactors such as calcium or magnesium ions, in evolution, luciferins vary little, one in particular, coelenterazine, is found in nine different animal, though in some of these, the animals obtain it through their diet. Conversely, luciferases vary widely in different species, Bioluminescence has arisen over forty times in evolutionary history. It was not until the nineteenth century that bioluminescence was properly investigated. The phenomenon is widely distributed among animal groups, especially in environments where dinoflagellates cause phosphorescence in the surface layers of water. On land it occurs in fungi, bacteria and some groups of invertebrates, in the laboratory, luciferase-based systems are used in genetic engineering and for biomedical research. Other researchers are investigating the possibility of using bioluminescent systems for street and decorative lighting, before the development of the safety lamp for use in coal mines, dried fish skins were used in Britain and Europe as a weak source of light. This experimental form of illumination avoided the necessity of using candles which risked sparking explosions of firedamp, another safe source of illumination in mines was bottles containing fireflies. In 1920, the American zoologist E. Newton Harvey published a monograph, The Nature of Animal Light, Harvey notes that Aristotle mentions light produced by dead fish and flesh, and that both Aristotle and Pliny the Elder mention light from damp wood. He also records that Robert Boyle experimented on these light sources, tuckey, in his posthumous 1818 Narrative of the Expedition to the Zaire, described catching the animals responsible for luminescence. He mentions pellucids, crustaceans, and cancers, under the microscope he described the luminous property to be in the brain, resembling a most brilliant amethyst about the size of a large pins head. Charles Darwin noticed bioluminescence in the sea, describing it in his Journal, While sailing in these latitudes on one very dark night, the sea presented a wonderful and most beautiful spectacle. There was a breeze, and every part of the surface. The vessel drove before her bows two billows of liquid phosphorus, and in her wake she was followed by a milky train. Darwin also observed a luminous jelly-fish of the genus Dianaea and noted that When the waves scintillate with bright green sparks, but there can be no doubt that very many other pelagic animals, when alive, are phosphorescent
3.
Chemiluminescence
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Chemiluminescence is the emission of light, as the result of a chemical reaction. There may also be limited emission of heat, the decay of this excited state to a lower energy level causes light emission. In theory, one photon of light should be given off for each molecule of reactant and this is equivalent to Avogadros number of photons per mole of reactant. In actual practice, non-enzymatic reactions seldom exceed 1% QC, quantum efficiency, in a chemical reaction, reactants collide to form a transition state, the enthalpic maximum in a reaction coordinate diagram, which proceeds to the product. Normally, reactants form products of chemical energy. The difference in energy between reactants and products, represented as Δ H r x n, is turned into heat, since vibrational energy is generally much greater than the thermal agitation, it rapidly disperses in the solvent through molecular rotation. This is how exothermic reactions make their solutions hotter, in a chemiluminescent reaction, the direct product of the reaction is an excited electronic state. Chemiluminescence differs from fluorescence or phosphorescence in that the excited state is the product of a chemical reaction rather than of the absorption of a photon. It is the antithesis of a reaction, in which light is used to drive an endothermic chemical reaction. Here, light is generated from an exothermic reaction. A standard example of chemiluminescence in the setting is the luminol test. Here, blood is indicated by luminescence upon contact with iron in hemoglobin, when chemiluminescence takes place in living organisms, the phenomenon is called bioluminescence. A light stick emits light by chemiluminescence, luminol in an alkaline solution with hydrogen peroxide in the presence of iron or copper, or an auxiliary oxidant, produces chemiluminescence. This is a reaction of phosphorus vapor, above the solid, with oxygen producing the excited states 2. Another gas phase reaction is the basis of nitric oxide detection in commercial analytic instruments applied to environmental air-quality testing, ozone is combined with nitric oxide to form nitrogen dioxide in an activated state. NO+O3 → NO2+ O2 The activated NO2 luminesces broadband visible to infrared light as it reverts to an energy state. A photomultiplier and associated electronics counts the photons that are proportional to the amount of NO present, the ozone reaction produces a photon count proportional to NO that is proportional to NO2 before it was converted to NO. In the case of a sample that contains both NO and NO2, the above reaction yields the amount of NO and NO2 combined in the air sample
4.
Europium
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Europium is a chemical element with symbol Eu and atomic number 63. It was isolated in 1901 and is named after the continent of Europe and it is a moderately hard, silvery metal which readily oxidizes in air and water. Being a typical member of the series, europium usually assumes the oxidation state +3. All europium compounds with oxidation state +2 are slightly reducing, Europium has no significant biological role and is relatively non-toxic compared to other heavy metals. Most applications of europium exploit the phosphorescence of europium compounds, Europium is one of the least abundant elements in the universe, only about 5×10−8% of all matter in the universe is europium. Europium is a metal with a hardness similar to that of lead. It crystallizes in a cubic lattice. Some properties of europium are strongly influenced by its half-filled electron shell, Europium has the second lowest melting point and the lowest density of all lanthanides. Europium becomes a superconductor when it is cooled below 1.8 K and this is because europium is divalent in the metallic state, and is converted into the trivalent state by the applied pressure. In the divalent state, the local magnetic moment suppresses the superconductivity. Europium is the most reactive rare earth element and it rapidly oxidizes in air, so that bulk oxidation of a centimeter-sized sample occurs within several days. This behavior is unusual to most lanthanides, which almost exclusively form compounds with a state of +3. The +2 state has an electron configuration 4f7 because the half-filled f-shell gives more stability, in terms of size and coordination number, europium and barium are similar. For example, the sulfates of both barium and europium are also highly insoluble in water, divalent europium is a mild reducing agent, oxidizing in air to form Eu compounds. In anaerobic, and particularly geothermal conditions, the divalent form is sufficiently stable that it tends to be incorporated into minerals of calcium and the other alkaline earths. This ion-exchange process is the basis of the europium anomaly. Bastnäsite tends to show less of a negative europium anomaly than does monazite, the development of easy methods to separate divalent europium from the other lanthanides made europium accessible even when present in low concentration, as it usually is. Naturally occurring europium is composed of 2 isotopes, 151Eu and 153Eu, while 153Eu is stable, 151Eu was recently found to be unstable to alpha decay with half-life of 5+11 −3×1018 years, giving about 1 alpha decay per two minutes in every kilogram of natural europium
5.
Strontium
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Strontium is a chemical element with symbol Sr and atomic number 38. An alkaline earth metal, strontium is a soft silver-white or yellowish metallic element that is highly reactive chemically, the metal forms a dark oxide layer when it is exposed to air. Strontium has physical and chemical properties similar to those of its two neighbors in the periodic table, calcium and barium. It occurs naturally in the minerals celestine, strontianite, and putnisite, natural stable strontium, on the other hand, is not hazardous to health. Strontium was first isolated as a metal in 1808 by Humphry Davy using the then-newly discovered process of electrolysis, the production of sugar from sugar beet was in the 19th century the largest application of strontium. At the peak of production of cathode ray tubes, as much as 75 percent of strontium consumption in the United States was used for the faceplate glass. With the displacement of cathode ray tubes by other display methods, Strontium is a divalent silvery metal with a pale yellow tint whose properties are mostly intermediate between and similar to those of its group neighbors calcium and barium. It is softer than calcium and harder than barium and its melting and boiling points are lower than those of calcium, barium continues this downward trend in the melting point, but not in the boiling point. The density of strontium is similarly intermediate between those of calcium and barium, three allotropes of metallic strontium exist, with transition points at 235 and 540 °C. The standard electrode potential for the Sr2+/Sr couple is −2.89 V, Strontium is intermediate between calcium and barium in its reactivity toward water, with which it reacts on contact to produce strontium hydroxide and hydrogen gas. Strontium metal burns in air to produce both strontium oxide and strontium nitride, but since it does not react with nitrogen below 380 °C, at room temperature, it forms only the oxide spontaneously. Besides the simple oxide SrO, the peroxide SrO2 can be made by oxidation of strontium metal under a high pressure of oxygen. Strontium hydroxide, Sr2, is a base, though it is not as strong as the hydroxides of barium or the alkali metals. Due to the size of the heavy s-block elements, including strontium. Organostrontium compounds contain one or more strontium–carbon bonds and they have been reported as intermediates in Barbier-type reactions. Organostrontium compounds tend to be similar to organoeuropium or organosamarium compounds due to the similar ionic radii of these elements. Most of these compounds can only be prepared at low temperatures, because of its extreme reactivity with oxygen and water, this element occurs naturally only in compounds with other elements, such as in the minerals strontianite and celestine. It is kept under a liquid such as mineral oil or kerosene to prevent oxidation
6.
Ultraviolet
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Ultraviolet is an electromagnetic radiation with a wavelength from 10 nm to 400 nm, shorter than that of visible light but longer than X-rays. UV radiation constitutes about 10% of the light output of the Sun. It is also produced by electric arcs and specialized lights, such as lamps, tanning lamps. Consequently, the effects of UV are greater than simple heating effects. Suntan, freckling and sunburn are familiar effects of over-exposure, along with risk of skin cancer. Living things on dry land would be damaged by ultraviolet radiation from the Sun if most of it were not filtered out by the Earths atmosphere. More-energetic, shorter-wavelength extreme UV below 121 nm ionizes air so strongly that it is absorbed before it reaches the ground, Ultraviolet is also responsible for the formation of bone-strengthening vitamin D in most land vertebrates, including humans. The UV spectrum thus has both beneficial and harmful to human health. Ultraviolet rays are invisible to most humans, the lens in a human eye ordinarily filters out UVB frequencies or higher, and humans lack color receptor adaptations for ultraviolet rays. Under some conditions, children and young adults can see ultraviolet down to wavelengths of about 310 nm, near-UV radiation is visible to some insects, mammals, and birds. Small birds have a fourth color receptor for ultraviolet rays, this gives birds true UV vision, reindeer use near-UV radiation to see polar bears, who are poorly visible in regular light because they blend in with the snow. UV also allows mammals to see urine trails, which is helpful for animals to find food in the wild. The males and females of some species look identical to the human eye. Ultraviolet means beyond violet, violet being the color of the highest frequencies of visible light, Ultraviolet has a higher frequency than violet light. He called them oxidizing rays to emphasize chemical reactivity and to them from heat rays. The terms chemical and heat rays were eventually dropped in favour of ultraviolet and infrared radiation, in 1878 the effect of short-wavelength light on sterilizing bacteria was discovered. By 1903 it was known the most effective wavelengths were around 250 nm, in 1960, the effect of ultraviolet radiation on DNA was established. The discovery of the ultraviolet radiation below 200 nm, named vacuum ultraviolet because it is absorbed by air, was made in 1893 by the German physicist Victor Schumann
7.
Fluorescence
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Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence, in most cases, the emitted light has a longer wavelength, and therefore lower energy, than the absorbed radiation. Fluorescent materials cease to glow immediately when the radiation source stops, unlike phosphorescence, Fluorescence also occurs frequently in nature in some minerals and in various biological states in many branches of the animal kingdom. An early observation of fluorescence was described in 1560 by Bernardino de Sahagún and it was derived from the wood of two tree species, Pterocarpus indicus and Eysenhardtia polystachya. The chemical compound responsible for this fluorescence is matlaline, which is the product of one of the flavonoids found in this wood. The name was derived from the fluorite, some examples of which contain traces of divalent europium. In a key experiment he used a prism to isolate ultraviolet radiation from sunlight, the specific frequencies of exciting and emitted light are dependent on the particular system. S0 is called the state of the fluorophore, and S1 is its first excited singlet state. A molecule in S1 can relax by various competing pathways and it can undergo non-radiative relaxation in which the excitation energy is dissipated as heat to the solvent. Excited organic molecules can also relax via conversion to a triplet state, relaxation from S1 can also occur through interaction with a second molecule through fluorescence quenching. Molecular oxygen is an extremely efficient quencher of fluorescence just because of its unusual triplet ground state, in most cases, the emitted light has a longer wavelength, and therefore lower energy, than the absorbed radiation, this phenomenon is known as the Stokes shift. The emitted radiation may also be of the wavelength as the absorbed radiation. Molecules that are excited through light absorption or via a different process can transfer energy to a second sensitized molecule, the fluorescence quantum yield gives the efficiency of the fluorescence process. It is defined as the ratio of the number of photons emitted to the number of photons absorbed, Φ = Number of photons emitted Number of photons absorbed The maximum fluorescence quantum yield is 1.0, each photon absorbed results in a photon emitted. Compounds with quantum yields of 0.10 are still considered quite fluorescent, thus, if the rate of any pathway changes, both the excited state lifetime and the fluorescence quantum yield will be affected. Fluorescence quantum yields are measured by comparison to a standard, the quinine salt quinine sulfate in a sulfuric acid solution is a common fluorescence standard. The fluorescence lifetime refers to the time the molecule stays in its excited state before emitting a photon. This is an instance of exponential decay, various radiative and non-radiative processes can de-populate the excited state
8.
Energy level
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A quantum mechanical system or particle that is bound—that is, confined spatially—can only take on certain discrete values of energy. This contrasts with classical particles, which can have any energy and these discrete values are called energy levels. The energy spectrum of a system with discrete energy levels is said to be quantized. In chemistry and atomic physics, a shell, or a principal energy level. The closest shell to the nucleus is called the 1 shell, followed by the 2 shell, then the 3 shell, the shells correspond with the principal quantum numbers or are labeled alphabetically with letters used in the X-ray notation. Each shell can contain only a number of electrons, The first shell can hold up to two electrons, the second shell can hold up to eight electrons, the third shell can hold up to 18. The general formula is that the nth shell can in principle hold up to 2 electrons, since electrons are electrically attracted to the nucleus, an atoms electrons will generally occupy outer shells only if the more inner shells have already been completely filled by other electrons. However, this is not a requirement, atoms may have two or even three incomplete outer shells. For an explanation of why electrons exist in these shells see electron configuration, if the potential energy is set to zero at infinite distance from the atomic nucleus or molecule, the usual convention, then bound electron states have negative potential energy. If an atom, ion, or molecule is at the lowest possible level, it. If it is at an energy level, it is said to be excited. If more than one quantum state is at the same energy. They are then called degenerate energy levels, quantized energy levels result from the relation between a particles energy and its wavelength. For a confined particle such as an electron in an atom, only stationary states with energies corresponding to integral numbers of wavelengths can exist, for other states the waves interfere destructively, resulting in zero probability density. Elementary examples that show mathematically how energy levels come about are the particle in a box, the first evidence of quantization in atoms was the observation of spectral lines in light from the sun in the early 1800s by Joseph von Fraunhofer and William Hyde Wollaston. The notion of levels was proposed in 1913 by Danish physicist Niels Bohr in the Bohr theory of the atom. The modern quantum mechanical theory giving an explanation of these levels in terms of the Schrödinger equation was advanced by Erwin Schrödinger and Werner Heisenberg in 1926. When the electron is bound to the atom in any closer value of n, assume there is one electron in a given atomic orbital in a hydrogen-like atom
