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For a system of particles with masses , with coordinates = that constitute a time-dependent random variable, the resulting Langevin equation is [2] [3] ¨ = ˙ + (), where () is the particle interaction potential; is the gradient operator such that () is the force calculated from the particle interaction potentials; the dot is a time derivative ...
In an ab initio MD simulation, the total energy of the system is calculated at each time step using density functional theory (DFT) or another method of quantum chemistry. The forces acting on each atom are then determined from the gradient of the energy with respect to the atomic coordinates, and the equations of motion are solved to predict ...
A molecular dynamics simulation requires the definition of a potential function, or a description of the terms by which the particles in the simulation will interact. In chemistry and biology this is usually referred to as a force field and in materials physics as an interatomic potential.
VisSim - system simulation and optional C-code generation of electrical, process, control, bio-medical, mechanical and UML State chart systems. Vortex (software) - a complete simulation platform featuring a realtime physics engine for rigid body dynamics, an image generator, desktop tools (Editor and Player) and more. Also available as Vortex ...
In a simulation this may be implemented by using small time steps for the simulation, using a fixed number of constraint-solving steps per time step, or solving constraints until they are met by a specific deviation. When approximating the constraints locally to first order, this is the same as the Gauss–Seidel method.
In computational chemistry, a constraint algorithm is a method for satisfying the Newtonian motion of a rigid body which consists of mass points. A restraint algorithm is used to ensure that the distance between mass points is maintained.
The various branches of the DEM family are the distinct element method proposed by Peter A. Cundall and Otto D. L. Strack in 1979, [5] the generalized discrete element method, [6] the discontinuous deformation analysis (DDA) and the finite-discrete element method concurrently developed by several groups (e.g., Munjiza and Owen).
Computational chemistry is a branch of chemistry that uses computer simulations to assist in solving chemical problems. [1] It uses methods of theoretical chemistry incorporated into computer programs to calculate the structures and properties of molecules , groups of molecules, and solids. [ 2 ]