Molecular dynamics From Wikipedia, the free encyclopedia Jump to: navigation, search Molecular dynamics (MD) is a form of computer simulation in which atoms...
91974
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Areas of Application There is a significant difference between the focus and methods used by chemists and physicists, and this is reflected in differences in ...
91975
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Design Constraints Design of a molecular dynamics simulation should account for the available computational power. Simulation size (n=number of particles),...
91976
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Microcanonical ensemble (NVE) In the microcanonical, or NVE ensemble, the system is isolated from changes in moles (N), volume (V) and energy (E). It...
91977
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Canonical ensemble (NVT) In the canonical ensemble, moles (N), volume (V) and temperature (T) are conserved. It is also sometimes called constant temperature ...
91978
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Isothermal-Isobaric (NPT) ensemble In the isothermal-isobaric ensemble, moles (N), pressure (P) and temperature (T) are conserved. In addition to a thermostat,...
91979
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Potentials in MD simulations Main article: Force field A molecular dynamics simulation requires the definition of a potential function, or a description of the...
91980
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Generalized ensembles The replica exchange method is a generalized ensemble. It was originally created to deal with the slow dynamics of disordered spin ...
91981
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Empirical potentials Empirical potentials used in chemistry are frequently called force fields, while those used in materials physics are called just empirical...
91982
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Semi-empirical potentials Semi-empirical potentials make use of the matrix representation from quantum mechanics. However, the values of the matrix elements...
91983
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Polarizable potentials Main article: Force field Most classical force fields implicitly include the effect of polarizability, e.g. by scaling up the partial...
91984
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Ab-initio methods In classical molecular dynamics, a single potential energy surface (usually the ground state) is represented in the force field. This is a...
91985
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Hybrid QM/MM QM (quantum-mechanical) methods are very powerful however they are computationally expensive, while the MM (classical or molecular mechanics)...
91986
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Coarse-graining and reduced representations At the other end of the detail scale are coarse-grained and lattice models. Instead of explicitly representing...
91987
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Examples of applications Molecular dynamics is used in many fields of science. First macromolecular MD simulation published (1977, Size: 500 atoms, Simulation...
91988
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Newton's laws of motion are three physical laws which provide relationships between the forces acting on a body and the motion of the body. They were first...
91989
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First law It is possible to select a set of reference frames, called inertial reference frames, observed from which a particle moves without any change in...
91990
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Second law Observed from an inertial reference frame, the net force on a particle is proportional to the time rate of change of its linear momentum: F = d (mv)...
91991
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Newton's first law: law of inertia Lex I: Corpus omne perseverare in statu suo quiescendi vel movendi uniformiter in directum, nisi quatenus a viribus...
91992
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Newton's second law: law of acceleration Lex II: Mutationem motus proportionalem esse vi motrici impressae, et fieri secundum lineam rectam qua vis illa...
91993
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Third law Whenever a particle A exerts a force on another particle B, B simultaneously exerts a force on A with the same magnitude in the opposite direction....
91994
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Newton's third law: law of reciprocal actions Lex III: Actioni contrariam semper et æqualem esse reactionem: sive corporum duorum actiones in se mutuo semper...
91995
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Importance and range of validity Newton's laws were verified by experiment and observation for over 200 years, and they are excellent approximations at the...
91996
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Relationship to the conservation laws In modern physics, the laws of conservation of momentum, energy, and angular momentum are of more general validity than...
91997
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Special relativity From Wikipedia, the free encyclopedia (Redirected from Special theory of relativity) Jump to: navigation, search For a generally accessible...
91998
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Postulates In his autobiographical notes published in November 1949 Einstein described how he had arrived at the two fundamental postulates on which he based...
91999
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Mass-energy equivalence See also: Mass in special relativity In addition to the papers referenced above—which give derivations of the Lorentz transformation...
92000
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Lack of an absolute reference frame The principle of relativity, which states that there is no preferred inertial reference frame, dates back to Galileo, and...
92001
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Consequences Main article: Consequences of special relativity Einstein has said that all of the consequences of special relativity can be derived from...
92002
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Reference frames, coordinates and the Lorentz transformation Full article: Lorentz transformations Diagram 1. Changing views of spacetime along the world line...
