NWChem is an

ab initio ''Ab initio'' ( ) is a Latin term meaning "from the beginning" and is derived from the Latin ''ab'' ("from") + ''initio'', ablative singular of ''initium'' ("beginning"). Etymology Circa 1600, from Latin, literally "from the beginning", from ab ...

computational chemistry Computational chemistry is a branch of chemistry that uses computer simulation to assist in solving chemical problems. It uses methods of theoretical chemistry, incorporated into computer programs, to calculate the structures and properties of m ...

software package which includes quantum chemical and molecular dynamics functionality. It was designed to run on high-performance parallel supercomputers as well as conventional workstation clusters. It aims to be scalable both in its ability to treat large problems efficiently, and in its usage of available parallel computing resources. NWChem has been developed by the Molecular Sciences Software group of the Theory, Modeling & Simulation program of the

Environmental Molecular Sciences Laboratory The Environmental Molecular Sciences Laboratory (EMSL, pronounced em-zul) is a Department of Energy, Office of Science facility at Pacific Northwest National Laboratory in Richland, Washington Richland () is a city in Benton County, Washington ...

(EMSL) at the Pacific Northwest National Laboratory (PNNL). The early implementation was funded by the EMSL Construction Project. NWChem is currently being redesigned and reimplemented for exascale computing platforms (NWChemEx ).

Capabilities

Molecular mechanics Molecular mechanics uses classical mechanics to model molecular systems. The Born–Oppenheimer approximation is assumed valid and the potential energy of all systems is calculated as a function of the nuclear coordinates using Force field (chemi ...

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 ...

* Hartree–Fock (self-consistent field method) *

Density functional theory Density-functional theory (DFT) is a computational quantum mechanical modelling method used in physics, chemistry and materials science to investigate the electronic structure (or nuclear structure) (principally the ground state) of many-body ...

Time-dependent density functional theory Time-dependent density-functional theory (TDDFT) is a quantum mechanical theory used in physics and chemistry to investigate the properties and dynamics of many-body systems in the presence of time-dependent potentials, such as electric or magne ...

Post-Hartree–Fock In computational chemistry, post-Hartree–Fock methods are the set of methods developed to improve on the Hartree–Fock (HF), or self-consistent field (SCF) method. They add electron correlation which is a more accurate way of including the rep ...

methods, including MP2 in the resolution of identity approximation (RI-MP2), multiconfigurational self-consistent-field (MCSCF) theory, selected configuration interaction (CI), Møller–Plesset perturbation theory (MP2, MP3, MP4),

configuration interaction Configuration interaction (CI) is a post-Hartree–Fock linear variational method for solving the nonrelativistic Schrödinger equation within the Born–Oppenheimer approximation for a quantum chemical multi-electron system. Mathematical ...

(CISD, CISDT, CISDTQ), and

coupled cluster Coupled cluster (CC) is a numerical technique used for describing many-body systems. Its most common use is as one of several post-Hartree–Fock ab initio quantum chemistry methods in the field of computational chemistry, but it is also used in ...

theory (CCSD, CCSDT, CCSDTQ, EOMCCSD, EOMCCSDT, EOMCCSDTQ). The Tensor Contraction Engine, or TCE, provides most of the functionality for the correlated methods, and can be used to develop additional many-body methods using a Python interface. A full list of approximate coupled-cluster methods is available on the website. *

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 ...

ONIOM The ONIOM (short for 'Our own n-layered Integrated molecular Orbital and Molecular mechanics') method is a computational approach developed by Morokuma and co-workers. ONIOM is a hybrid method that enables different ab initio, semi-empirical, or m ...

References

External links

*
NWChem Github repository

Graphical shells

* ECCE (official GUI for NWChem), supports input generation, remote submission, analysis, extensive visualization *

Ascalaph Designer Ascalaph Designer is a computer program for general purpose molecular modelling for molecular design and simulations. It provides a graphical environment for the common programs of quantum and classical molecular modelling ORCA, NWChem, Firefly, ...

, a free and open source software package for model construction
Chemcraft
a proprietary software for visualization and analysis of results Computational chemistry software Free chemistry software Chemistry software for Linux {{Chemistry software