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RRKM Theory
The Rice–Ramsperger–Kassel–Marcus (RRKM) theory is a theory of chemical reactivity. It was developed by Rice and Ramsperger in 1927 and Kassel in 1928 (RRK theory) and generalized (into the RRKM theory) in 1952 by Marcus who took the transition state theory developed by Eyring in 1935 into account. These methods enable the computation of simple estimates of the unimolecular reaction rates The reaction rate or rate of reaction is the speed at which a chemical reaction takes place, defined as proportional to the increase in the concentration of a product per unit time and to the decrease in the concentration of a reactant per unit ... from a few characteristics of the potential energy surface. Assumption Assume that the molecule consists of harmonic oscillators, which are connected and can exchange energy with each other. * Assume the possible excitation energy of the molecule to be , which enables the reaction to occur. * The rate of intra-molecular energy dis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reactivity (chemistry)
In chemistry, reactivity is the impulse for which a chemical substance undergoes a chemical reaction, either by itself or with other materials, with an overall release of energy. ''Reactivity'' refers to: * the chemical reactions of a single substance, * the chemical reactions of two or more substances that interact with each other, * the systematic study of sets of reactions of these two kinds, * methodology that applies to the study of reactivity of chemicals of all kinds, * experimental methods that are used to observe these processes * theories to predict and to account for these processes. The chemical reactivity of a single substance (reactant) covers its behavior in which it: * Decomposes * Forms new substances by addition of atoms from another reactant or reactants * Interacts with two or more other reactants to form two or more products The chemical reactivity of a substance can refer to the variety of circumstances (conditions that include temperature, pressure, prese ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oscar Knefler Rice
Oscar, OSCAR, or The Oscar may refer to: People * Oscar (given name), an Irish- and English-language name also used in other languages; the article includes the names Oskar, Oskari, Oszkár, Óscar, and other forms. * Oscar (Irish mythology), legendary figure, son of Oisín and grandson of Finn mac Cumhall Places * Oscar, Kentucky, an unincorporated community * Oscar, Louisiana, an unincorporated community * Oscar, Missouri, an unincorporated community * Oscar, Oklahoma, an unincorporated community * Oscar, Pennsylvania, an unincorporated community * Oscar, Texas, an unincorporated community * Oscar, West Virginia, an unincorporated community * Lake Oscar (other) * Oscar Township, Otter Tail County, Minnesota, a civil township Animals * Oscar (bionic cat), a cat that had implants after losing both hind paws * Oscar (bull), #16, (d. 1983) a ProRodeo Hall of Fame bucking bull * Oscar (fish), ''Astronotus ocellatus'' * Oscar (therapy cat), cat purported to pred ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herman Carl Ramsperger
Herman may refer to: People * Herman (name), list of people with this name * Saint Herman (other) * Peter Noone (born 1947), known by the mononym Herman Places in the United States * Herman, Arkansas * Herman, Michigan * Herman, Minnesota * Herman, Nebraska * Herman, Pennsylvania * Herman, Dodge County, Wisconsin * Herman, Shawano County, Wisconsin * Herman, Sheboygan County, Wisconsin Place in India * Herman (Village) Other uses * ''Herman'' (comic strip) * ''Herman'' (film), a 1990 Norwegian film * Herman the Bull, a bull used for genetic experiments in the controversial lactoferrin project of GenePharming, Netherlands * Herman the Clown ( fi, Pelle Hermanni), a Finnish TV clown from children's TV show performed by Veijo Pasanen * Herman's Hermits, a British pop combo * Herman cake (also called Hermann), a type of sourdough bread starter or Amish Friendship Bread starter * ''Herman'' (album) by 't Hof Van Commerce See also * Hermann (other) * Arman ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Louis Stevenson Kassel , names sometimes translated to English as "Louis"
{{disambiguation ...
Louis may refer to: * Louis (coin) * Louis (given name), origin and several individuals with this name * Louis (surname) * Louis (singer), Serbian singer * HMS ''Louis'', two ships of the Royal Navy See also Derived or associated terms * Lewis (other) * Louie (other) * Luis (other) * Louise (other) * Louisville (other) * Louis Cruise Lines * Louis dressing, for salad * Louis Quinze, design style Associated names * * Chlodwig, the origin of the name Ludwig, which is translated to English as "Louis" * Ladislav and László - names sometimes erroneously associated with "Louis" * Ludovic, Ludwig, Ludwick, Ludwik Ludwik () is a Polish given name. Notable people with the name include: * Ludwik Czyżewski, Polish WWII general * Ludwik Fleck (1896–1961), Polish medical doctor and biologist * Ludwik Gintel (1899–1973), Polish-Israeli Olympic soccer player ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rudolph A
Rudolph or Rudolf may refer to: People * Rudolph (name), the given name including a list of people with the name Religious figures * Rudolf of Fulda (died 865), 9th century monk, writer and theologian * Rudolf von Habsburg-Lothringen (1788–1831), Archbishop of Olomouc and member of the House of Habsburg-Lorraine Royalty and nobility *Rudolph I (other) * Rudolph II (other) *Rudolph III (other) * Rudolph of France (died 936) * Rudolph I of Germany (1218–1291) * Rudolf II, Holy Roman Emperor (1552–1612) * Rudolph, Prince of Anhalt-Zerbst (1576–1621) * Rudolf, Crown Prince of Austria (1858–1889), son and heir of Emperor Franz Joseph I of Austria and Empress Elisabeth of Austria (died at Mayerling) Places * Rudolph Glacier, Antarctica * Rudolph, South Dakota, US * Rudolph, Wisconsin, US, a village * Rudolph (town), Wisconsin, adjacent to the village * Rudolf Island, northernmost island of Europe * Lake Rudolf, now Lake Turkana, in Kenya A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transition State Theory
In chemistry, transition state theory (TST) explains the reaction rates of elementary chemical reactions. The theory assumes a special type of chemical equilibrium (quasi-equilibrium) between reactants and activated transition state complexes. TST is used primarily to understand qualitatively how chemical reactions take place. TST has been less successful in its original goal of calculating absolute reaction rate constants because the calculation of absolute reaction rates requires precise knowledge of potential energy surfaces, but it has been successful in calculating the standard enthalpy of activation (Δ''H''‡, also written Δ‡''H''ɵ), the standard entropy of activation (Δ''S''‡ or Δ‡''S''ɵ), and the standard Gibbs energy of activation (Δ''G''‡ or Δ‡''G''ɵ) for a particular reaction if its rate constant has been experimentally determined. (The ‡ notation refers to the value of interest ''at the transition state''; Δ''H''‡ is the difference between the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henry Eyring (chemist)
Henry Eyring (February 20, 1901 – December 26, 1981) was a Mexico-born United States theoretical chemist whose primary contribution was in the study of chemical reaction rates and intermediates. History Eyring, a third-generation member of the Church of Jesus Christ of Latter-day Saints (LDS Church), was reared on a cattle ranch in Colonia Juárez, Chihuahua, a Mormon colony, for the first 11 years of his life. His father, Edward Christian Eyring, practiced plural marriage; Edward married Caroline Romney (1893) and her sister Emma Romney (1903), both daughters of Miles Park Romney, the great-grandfather of Mitt Romney. In July 1912, the Eyrings and about 4,200 other immigrants were driven out of Mexico by violent insurgents during the Mexican Revolution and moved to El Paso, Texas. After living in El Paso for approximately one year, the Eyrings relocated to Pima, Arizona, where he completed high school and showed a special aptitude for mathematics and science. He also studied ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reaction Rates
The reaction rate or rate of reaction is the speed at which a chemical reaction takes place, defined as proportional to the increase in the concentration of a product per unit time and to the decrease in the concentration of a reactant per unit time. Reaction rates can vary dramatically. For example, the oxidative rusting of iron under Earth's atmosphere is a slow reaction that can take many years, but the combustion of cellulose in a fire is a reaction that takes place in fractions of a second. For most reactions, the rate decreases as the reaction proceeds. A reaction's rate can be determined by measuring the changes in concentration over time. Chemical kinetics is the part of physical chemistry that concerns how rates of chemical reactions are measured and predicted, and how reaction-rate data can be used to deduce probable reaction mechanisms. The concepts of chemical kinetics are applied in many disciplines, such as chemical engineering, enzymology and environmental engi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potential Energy Surface
A potential energy surface (PES) describes the energy of a system, especially a collection of atoms, in terms of certain parameters, normally the positions of the atoms. The surface might define the energy as a function of one or more coordinates; if there is only one coordinate, the surface is called a ''potential energy curve'' or energy profile. An example is the Morse/Long-range potential. It is helpful to use the analogy of a landscape: for a system with two degrees of freedom (e.g. two bond lengths), the value of the energy (analogy: the height of the land) is a function of two bond lengths (analogy: the coordinates of the position on the ground). The PES concept finds application in fields such as chemistry and physics, especially in the theoretical sub-branches of these subjects. It can be used to theoretically explore properties of structures composed of atoms, for example, finding the minimum energy shape of a molecule or computing the rates of a chemical reaction. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harmonic Oscillators
In classical mechanics, a harmonic oscillator is a system that, when displaced from its equilibrium position, experiences a restoring force ''F'' proportional to the displacement ''x'': \vec F = -k \vec x, where ''k'' is a positive constant. If ''F'' is the only force acting on the system, the system is called a simple harmonic oscillator, and it undergoes simple harmonic motion: sinusoidal oscillations about the equilibrium point, with a constant amplitude and a constant frequency (which does not depend on the amplitude). If a frictional force (damping) proportional to the velocity is also present, the harmonic oscillator is described as a damped oscillator. Depending on the friction coefficient, the system can: * Oscillate with a frequency lower than in the undamped case, and an amplitude decreasing with time (underdamped oscillator). * Decay to the equilibrium position, without oscillations (overdamped oscillator). The boundary solution between an underdamped oscillato ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reaction Coordinate
In chemistry, a reaction coordinate is an abstract one-dimensional coordinate which represents progress along a reaction pathway. It is usually a geometric parameter that changes during the conversion of one or more molecular entities. In molecular dynamics simulations, a reaction coordinate is called collective variable. These coordinates can sometimes represent a real coordinate system (such as bond length, bond angle...), although, for more complex reactions especially, this can be difficult (and non geometric parameters are used, e.g., bond order). Reaction coordinate is distinct from extent of reaction, a different parameter of reaction progress, which is a measure of the ''composition'' of the reaction system. (Free) energy is often plotted against reaction coordinate(s) to demonstrate in some schematic form the potential energy profile (an intersection of a potential energy surface) associated with the reaction. In the formalism of transition-state theory the reaction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transition State Theory
In chemistry, transition state theory (TST) explains the reaction rates of elementary chemical reactions. The theory assumes a special type of chemical equilibrium (quasi-equilibrium) between reactants and activated transition state complexes. TST is used primarily to understand qualitatively how chemical reactions take place. TST has been less successful in its original goal of calculating absolute reaction rate constants because the calculation of absolute reaction rates requires precise knowledge of potential energy surfaces, but it has been successful in calculating the standard enthalpy of activation (Δ''H''‡, also written Δ‡''H''ɵ), the standard entropy of activation (Δ''S''‡ or Δ‡''S''ɵ), and the standard Gibbs energy of activation (Δ''G''‡ or Δ‡''G''ɵ) for a particular reaction if its rate constant has been experimentally determined. (The ‡ notation refers to the value of interest ''at the transition state''; Δ''H''‡ is the difference between the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
