 An excimer[1] (originally short for excited dimer) is a short-lived dimeric or heterodimeric molecule formed from two species, at least one of which is in an electronic excited state. Excimers are often diatomic and are formed between two atoms or molecules that would not bond if both were in the ground state. The lifetime of an excimer is very short, on the order of nanoseconds. Image File history File links Excimer_energy-diagram. ...
Sucrose, or common table sugar, is composed of glucose and fructose. ...
3D (left and center) and 2D (right) representations of the terpenoid molecule atisane. ...
For other uses, see Electron (disambiguation). ...
After absorbing energy, an electron may jump from the ground state to a higher energy excited state. ...
In physics, the ground state of a quantum mechanical system is its lowest-energy state. ...
To help compare orders of magnitude of different times this page lists times between 10−9 seconds and 10−8 seconds (1 nanosecond and 10 nanoseconds) See also times of other orders of magnitude. ...
Formation and decay
 Under the molecular orbital formalism, a typical ground-state molecule has electrons in the lowest possible energy levels. According to Hund's rule, at most two electrons can occupy a given orbital, and if an orbital contains two electrons they must be in opposite spin states. The highest occupied molecular orbital is called the HOMO and the lowest unoccupied molecular orbital is called the LUMO; the energy gap between these two states is known as the HOMO/LUMO gap. If the molecule absorbs light whose energy is larger than this gap, an electron in the HOMO may be excited to the LUMO. This is called the molecule's excited state. Image File history File links Molecule_HOMO-LUMO_diagram. ...
In chemistry, a molecular orbital is a region in which an electron may be found in a molecule. ...
For other uses, see Electron (disambiguation). ...
Hunds rule is a principle of physical chemistry which states that before any two electrons occupy an orbital in a subshell, other orbitals in the same subshell must first each contain one electron. ...
In physics, spin refers to the angular momentum intrinsic to a body, as opposed to orbital angular momentum, which is the motion of its center of mass about an external point. ...
HOMO and LUMO are acronyms for highest occupied molecular orbital and lowest unoccupied molecular orbital, respectively. ...
After absorbing energy, an electron may jump from the ground state to a higher energy excited state. ...
Excimers are only formed when one of the dimer components is in the excited state. When the excimer returns to the ground state, its components dissociate and often repel each other. The wavelength of an excimer's emission is longer (smaller energy) than that of the excited monomer's emission. An excimer can thus be measured by fluorescent emissions. In chemistry, a monomer (from Greek mono one and meros part) is a small molecule that may become chemically bonded to other monomers to form a polymer. ...
Because excimer formation is dependent on a bimolecular interaction, it is promoted by high monomer density. Low-density conditions produce excited monomers that decay to the ground state before they interact with an unexcited monomer to form an excimer. Molecularity in chemistry is the number of colliding molecules that are involved in a single reaction step. ...
Usage note The term excimer (excited state complex) is, strictly speaking, limited to cases in which a true dimer is formed; that is, both components of the dimer are the same molecule or atom. The term exciplex refers to the heterodimeric case; however, common usage expands excimer to cover this situation.
Examples and use Heterodimeric diatomic complexes involving a noble gas and a halide, such as xenon chloride, are common in the construction of excimer lasers, which are excimers' most common application. These lasers take advantage of the fact that excimer components have attractive interactions in the excited state and repulsive interactions in the ground state. The molecule pyrene is another canonical example of an excimer that has found applications in biophysics to evaluate the distance between biomolecules[2]. Neon, like all noble gases, has a full valence (outermost) electron shell. ...
A halide is a binary compound, of which one part is a halogen atom and the other part is an element or radical that is less electronegative than the halogen, to make a fluoride, chloride, bromide, iodide, or astatide compound. ...
An excimer laser is a form of ultraviolet chemical laser which is commonly used in eye surgery and semiconductor manufacturing. ...
Flash point non-flammable R/S statement R: 36/37/38-45-53 S: 24/25-26-36 RTECS number UR2450000 Supplementary data page Structure and properties n, εr, etc. ...
A representation of the 3D structure of myoglobin, showing coloured alpha helices. ...
In organic chemistry many reactions occur through an exciplex for example those of simple arene compounds with alkenes: [3] The reactions of benzene and their products depicted are a [2+2]cycloaddition to the ortho product (A) [4]., a [2+3]cycloaddition to the meta product (B) [5] and the [2+4]cycloaddition to the para product (C) [6] with simple alkenes such as the isomers of 2-butene. In these reactions it is the arene that is excited. Organic chemistry is a specific discipline within chemistry which involves the scientific study of the structure, properties, composition, reactions, and preparation (by synthesis or by other means) of chemical compounds consisting primarily of carbon and hydrogen, which may contain any number of other elements, including nitrogen, oxygen, halogens as well...
An aromatic hydrocarbon (abbreviated as AH) or arene [1] is a hydrocarbon, the molecular structure of which incorporates one or more planar sets of six carbon atoms that are connected by delocalised electrons numbering the same as if they consisted of alternating single and double covalent bonds. ...
For benzine, see petroleum ether. ...
Arene substitution patterns are part of organic chemistry IUPAC nomenclature and pinpoint the position of substituents other than hydrogen in relation to each other on an aromatic hydrocarbon. ...
1-butene cis-2-butene trans-2-butene methylpropene There are four isomers of alkenes which have the chemical formula C4H8. ...
As a general rule the regioselectivity is in favor of the ortho adduct at the expense of the meta adduct when the amount of charge transfer taking place in the exciplex increases Image File history File links Size of this preview: 800 × 571 pixelsFull resolution (828 × 591 pixel, file size: 8 KB, MIME type: image/png) Arene photo cycloadditions I, the creator of this work, hereby grant the permission to copy, distribute and/or modify this document under the terms of the...
In chemistry, regioselectivity is the preference of one direction of chemical bond making or breaking over all other possible directions. ...
References - ^ Birks, JB "Excimers", Rep. Prog. Phys. 1975, 38, 903-974.
- ^ Conibear PB, Bagshaw CR, Fajer PG, Kovacs M, Malnasi-Csizmadia A. (2003). Myosin cleft movement and its coupling to actomyosin dissociation. Nat Struct Biol 10(10):831-5.
- ^ Photochemistry of Arenes—Reloaded Jochen Mattay Angew. Chem. Int. Ed. 2007, 46, 663 – 665 doi:10.1002/anie.200603337
- ^ 1-cyanobicyclo[4.2.0]octa-2,4-dienes and their synthesis United States Patent 2,805,242 Issue Date: September 3, 1957 Link
- ^ A Photochemical 1,3 Cycloaddition of Olefins to Benzene K. E. Wilzbach and Louis Kaplan J. Am. Chem. Soc.; 1966; 88(9) pp 2066 - 2067; doi:10.1021/ja00961a052
- ^ Photoaddition of benzene to olefins. II. Stereospecific 1,2 and 1,4 cycloadditions Kenneth E. Wilzbach and Louis Kaplan J. Am. Chem. Soc.; 1971; 93(8) pp 2073 - 2074; doi:10.1021/ja00737a052
Angewandte Chemie or Angewandte Chemie International Edition is the chemistry journal of the Gesellschaft Deutscher Chemiker (Society of German Chemists). ...
A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ...
The Journal of the American Chemical Society (usually abbreviated as , or JACS), is a peer-reviewed scientific journal, published since 1879 by the American Chemical Society. ...
A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ...
The Journal of the American Chemical Society (usually abbreviated as , or JACS), is a peer-reviewed scientific journal, published since 1879 by the American Chemical Society. ...
A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ...
See also The neck of a guitar showing the first four frets. ...
An excimer laser is a form of ultraviolet chemical laser which is commonly used in eye surgery and semiconductor manufacturing. ...
A krypton fluoride laser (KrF laser) utilizes the small but utilizable chemical property of krypton gas and the strong oxidizing power of fluorine gas to produce laser between the two with the stimulation of a strong electron energy input. ...
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