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NAMD
Nanoscale Molecular Dynamics (NAMD, formerly Not Another Molecular Dynamics Program) is computer software for molecular dynamics simulation, written using the Charm++ parallel programming model. It is noted for its parallel efficiency and is often used to simulate large systems (millions of atoms). It has been developed by the collaboration of the Theoretical and Computational Biophysics Group (TCB) and the Parallel Programming Laboratory (PPL) at the University of Illinois at Urbana–Champaign. It was introduced in 1995 by Nelson ''et al.'' as a parallel molecular dynamics code enabling interactive simulation by linking to the visualization code VMD. NAMD has since matured, adding many features and scaling beyond 500,000 processor cores. NAMD has an interface to quantum chemistry packages ORCA and MOPAC, as well as a scripted interface to many other quantum packages. Together with Visual Molecular Dynamics (VMD) and QwikMD, NAMD's interface provides access to hybrid QM/MM simula ...
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Charm++
Charm++ is a parallel object-oriented programming paradigm based on C++ and developed in the Parallel Programming Laboratory at the University of Illinois at Urbana–Champaign. Charm++ is designed with the goal of enhancing programmer productivity by providing a high-level abstraction of a parallel program while at the same time delivering good performance on a wide variety of underlying hardware platforms. Programs written in Charm++ are decomposed into a number of cooperating message-driven objects called ''chares''. When a programmer invokes a method on an object, the Charm++ runtime system sends a message to the invoked object, which may reside on the local processor or on a remote processor in a parallel computation. This message triggers the execution of code within the chare to handle the message asynchronously. Chares may be organized into indexed collections called ''chare arrays'' and messages may be sent to individual chares within a chare array or to the entire chare a ...
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Visual Molecular Dynamics
Visual Molecular Dynamics (VMD) is a molecular modelling and visualization computer program. VMD is developed mainly as a tool to view and analyze the results of molecular dynamics simulations. It also includes tools for working with volumetric data, sequence data, and arbitrary graphics objects. Molecular scenes can be exported to external rendering tools such as POV-Ray, RenderMan, Tachyon, Virtual Reality Modeling Language (VRML), and many others. Users can run their own Tcl and Python scripts within VMD as it includes embedded Tcl and Python interpreters. VMD runs on Unix, Apple Mac macOS, and Microsoft Windows. VMD is available to non-commercial users under a distribution-specific license which permits both use of the program and modification of its source code, at no charge. History VMD has been developed under the aegis of principal investigator Klaus Schulten in the Theoretical and Computational Biophysics group at the Beckman Institute for Advanced Science and Technolog ...
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Molecular Dynamics
Molecular dynamics (MD) is a computer simulation method for analyzing the physical movements of atoms and molecules. The atoms and molecules are allowed to interact for a fixed period of time, giving a view of the dynamic "evolution" of the system. In the most common version, the trajectories of atoms and molecules are determined by numerically solving Newton's equations of motion for a system of interacting particles, where forces between the particles and their potential energies are often calculated using interatomic potentials or molecular mechanical force fields. The method is applied mostly in chemical physics, materials science, and biophysics. Because molecular systems typically consist of a vast number of particles, it is impossible to determine the properties of such complex systems analytically; MD simulation circumvents this problem by using numerical methods. However, long MD simulations are mathematically ill-conditioned, generating cumulative errors in ...
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Comparison Of Software For Molecular Mechanics Modeling
This is a list of computer programs that are predominantly used for molecular mechanics calculations. See also *Car–Parrinello molecular dynamics *Comparison of force-field implementations *Comparison of nucleic acid simulation software *List of molecular graphics systems *List of protein structure prediction software *List of quantum chemistry and solid-state physics software * List of software for Monte Carlo molecular modeling * List of software for nanostructures modeling *Molecular design software *Molecular dynamics *Molecular modeling on GPUs *Molecule editor A molecule editor is a computer program for creating and modifying representations of chemical structures. Molecule editors can manipulate chemical structure representations in either a simulated two-dimensional space or three-dimensional space, v ... Notes and references External linksSINCRISLinu ...
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Molecular Dynamics
Molecular dynamics (MD) is a computer simulation method for analyzing the physical movements of atoms and molecules. The atoms and molecules are allowed to interact for a fixed period of time, giving a view of the dynamic "evolution" of the system. In the most common version, the trajectories of atoms and molecules are determined by numerically solving Newton's equations of motion for a system of interacting particles, where forces between the particles and their potential energies are often calculated using interatomic potentials or molecular mechanical force fields. The method is applied mostly in chemical physics, materials science, and biophysics. Because molecular systems typically consist of a vast number of particles, it is impossible to determine the properties of such complex systems analytically; MD simulation circumvents this problem by using numerical methods. However, long MD simulations are mathematically ill-conditioned, generating cumulative errors in ...
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University Of Illinois At Urbana–Champaign
The University of Illinois Urbana-Champaign (U of I, Illinois, University of Illinois, or UIUC) is a public land-grant research university in Illinois in the twin cities of Champaign and Urbana. It is the flagship institution of the University of Illinois system and was founded in 1867. Enrolling over 56,000 undergraduate and graduate students, the University of Illinois is one of the largest public universities by enrollment in the country. The University of Illinois Urbana-Champaign is a member of the Association of American Universities and is classified among "R1: Doctoral Universities – Very high research activity". In fiscal year 2019, research expenditures at Illinois totaled $652 million. The campus library system possesses the second-largest university library in the United States by holdings after Harvard University. The university also hosts the National Center for Supercomputing Applications and is home to the fastest supercomputer on a university campus. The ...
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QM/MM
The hybrid QM/MM (quantum mechanics/molecular mechanics) approach is a molecular simulation method that combines the strengths of ''ab initio'' QM calculations (accuracy) and MM (speed) approaches, thus allowing for the study of chemical processes in solution and in proteins. The QM/MM approach was introduced in the 1976 paper of Warshel and Levitt. They, along with Martin Karplus, won the 2013 Nobel Prize in Chemistry for "the development of multiscale models for complex chemical systems". Efficiency An important advantage of QM/MM methods is their efficiency. The cost of doing classical molecular mechanics (MM) simulations in the most straightforward case scales as ''O''(''N''2), where ''N'' is the number of atoms in the system. This is mainly due to electrostatic interactions term (every particle interacts with everything else). However, use of cutoff radius, periodic pair-list updates and more recently the variations of the particle mesh Ewald (PME) method has reduced this ...
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MOPAC
MOPAC is a popular computer program used in computational chemistry. It is designed to implement semi-empirical quantum chemistry algorithms, and it runs on Windows, Mac, and Linux. MOPAC2016 is the current version. MOPAC2016 is able to perform calculations on small molecules and enzymes using PM7, PM6, PM3, AM1, MNDO, and RM1. The Sparkle model (for lanthanide chemistry) is also available. Academic users can use this program for free, whereas government and commercial users must purchase the software. MOPAC was largely written by Michael Dewar's research group at the University of Texas at Austin. Its name is derived from ''Molecular Orbital PACkage'', and it is also a pun on the Mopac Expressway that runs around Austin. MOPAC2007 included the new Sparkle/AM1, Sparkle/PM3, RM1 and PM6 models, with an increased emphasis on solid state capabilities. However, it does not have yet MINDO/3, PM5, analytical derivatives, the Tomasi solvation model and intersystem crossing. MOPAC2007 wa ...
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Quantum Chemistry
Quantum chemistry, also called molecular quantum mechanics, is a branch of physical chemistry focused on the application of quantum mechanics to chemical systems, particularly towards the quantum-mechanical calculation of electronic contributions to physical and chemical properties of Molecule, molecules, Material, materials, and solutions at the atomic level. These calculations include systematically applied approximations intended to make calculations computationally feasible while still capturing as much information about important contributions to the computed Wave function, wave functions as well as to observable properties such as structures, spectra, and thermodynamic properties. Quantum chemistry is also concerned with the computation of quantum effects on molecular dynamics and chemical kinetics. Chemists rely heavily on spectroscopy through which information regarding the Quantization (physics), quantization of energy on a molecular scale can be obtained. Common metho ...
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Atom
Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and a number of neutrons. Only the most common variety of hydrogen has no neutrons. Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms. Atoms are extremely small, typically around 100 picometers across. They are so small that accurately predicting their behavior using classical physics, as if they were tennis balls for example, is not possible due to quantum effects. More than 99.94% of an atom's mass is in the nucleus. The protons have a positive electric charge, the electrons have a negative electric charge, and the neutrons have no electric charge. If the number of protons and electrons are equal, then the atom is electrically neutral. If an atom has more or fewer electrons than protons, then it has an overall negative or positive charge, respectively – such atoms are called ions. The electrons of an atom are a ...
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Software
Software is a set of computer programs and associated documentation and data. This is in contrast to hardware, from which the system is built and which actually performs the work. At the lowest programming level, executable code consists of machine language instructions supported by an individual processor—typically a central processing unit (CPU) or a graphics processing unit (GPU). Machine language consists of groups of binary values signifying processor instructions that change the state of the computer from its preceding state. For example, an instruction may change the value stored in a particular storage location in the computer—an effect that is not directly observable to the user. An instruction may also invoke one of many input or output operations, for example displaying some text on a computer screen; causing state changes which should be visible to the user. The processor executes the instructions in the order they are provided, unless it is instructed ...
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