![]() | |
Original author(s) | James Stewart |
---|---|
Developer(s) | Molecular Sciences Software Institute |
Initial release | 1983 |
Stable release | 22.1.1 / 29 January 2024 |
Repository | github |
Written in | Fortran |
Operating system | Linux, MacOS, Microsoft Windows |
Available in | English |
Type | Computational chemistry |
License | LGPL 3.0 |
Website | openmopac |
MOPAC is a computer program used in computational chemistry. It is designed to implement semi-empirical quantum chemistry algorithms, and it runs on Windows, MacOS, and Linux. [1]
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) [2] is also available. Academic users can use this program for free, whereas government and commercial users must purchase the software. [3]
MOPAC was largely written by Michael Dewar's research group at the University of Texas at Austin. [4] Its name is derived from Molecular Orbital PACkage, and it is also a pun on the Mopac Expressway that runs around Austin. [5]
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 MINDO/3, PM5, analytical derivatives, the Tomasi solvation model or intersystem crossing. MOPAC2007 was followed by the release of MOPAC2009 in 2008, which presents many improved features. [6]
Later versions were no longer public-domain software, as were the earlier versions, such as MOPAC6 and MOPAC7. However, there were efforts to keep MOPAC7 working as open source software. An open source version of MOPAC7 for Linux is also available. [7] In 2006, the author of MOPAC, James Stewart, released a public-domain version of MOPAC7 entirely written in Fortran 90, called MOPAC7.1.
In 2022, MOPAC2016 was released as openMopac [8] and opened sourced under the LGPL license.
In computing, cross-platform software is computer software that is designed to work in several computing platforms. Some cross-platform software requires a separate build for each platform, but some can be directly run on any platform without special preparation, being written in an interpreted language or compiled to portable bytecode for which the interpreters or run-time packages are common or standard components of all supported platforms.
DJ's GNU Programming Platform (DJGPP) is a software development suite for Intel 80386-level and above, IBM PC compatibles which supports DOS operating systems. It is guided by DJ Delorie, who began the project in 1989. It is a port of the GNU Compiler Collection (GCC), and mostly GNU utilities such as Bash, find, tar, ls, GAWK, sed, and ld to DOS Protected Mode Interface (DPMI). Supported languages include C, C++, Objective-C/C++, Ada, Fortran, and Pascal.
Gaussian is a general purpose computational chemistry software package initially released in 1970 by John Pople and his research group at Carnegie Mellon University as Gaussian 70. It has been continuously updated since then. The name originates from Pople's use of Gaussian orbitals to speed up molecular electronic structure calculations as opposed to using Slater-type orbitals, a choice made to improve performance on the limited computing capacities of then-current computer hardware for Hartree–Fock calculations. The current version of the program is Gaussian 16. Originally available through the Quantum Chemistry Program Exchange, it was later licensed out of Carnegie Mellon University, and since 1987 has been developed and licensed by Gaussian, Inc.
MNDO, or Modified Neglect of Diatomic Overlap is a semi-empirical method for the quantum calculation of molecular electronic structure in computational chemistry. It is based on the Neglect of Diatomic Differential Overlap integral approximation. Similarly, this method replaced the earlier MINDO method. It is part of the MOPAC program and was developed in the group of Michael Dewar. It is also part of the AMPAC, GAMESS (US), PC GAMESS, GAMESS (UK), Gaussian, ORCA and CP2K programs.
Austin Model 1, or AM1, is a semi-empirical method for the quantum calculation of molecular electronic structure in computational chemistry. It is based on the Neglect of Differential Diatomic Overlap integral approximation. Specifically, it is a generalization of the modified neglect of differential diatomic overlap approximation. Related methods are PM3 and the older MINDO.
PM3, or Parametric Method 3, is a semi-empirical method for the quantum calculation of molecular electronic structure in computational chemistry. It is based on the Neglect of Differential Diatomic Overlap integral approximation.
Amsterdam Density Functional (ADF) is a program for first-principles electronic structure calculations that makes use of density functional theory (DFT). ADF was first developed in the early seventies by the group of E. J. Baerends from the Vrije Universiteit in Amsterdam, and by the group of T. Ziegler from the University of Calgary. Nowadays many other academic groups are contributing to the software. Software for Chemistry & Materials (SCM), formerly known as Scientific Computing & Modelling is a spin-off company from the Baerends group. SCM has been coordinating the development and distribution of ADF since 1995. Together with the rise in popularity of DFT in the nineties, ADF has become a popular computational chemistry software package used in the industrial and academic research. ADF excels in spectroscopy, transition metals, and heavy elements problems. A periodic structure counterpart of ADF named BAND is available to study bulk crystals, polymers, and surfaces. The Amsterdam Modeling Suite has expanded beyond DFT since 2010, with the semi-empirical MOPAC code, the Quantum ESPRESSO plane wave code, a density-functional based tight binding (DFTB) module, a reactive force field module ReaxFF, and an implementation of Klamt's COSMO-RS method, which also includes COSMO-SAC, UNIFAC, and QSPR.
Ghemical is a computational chemistry software package written in C++ and released under the GNU General Public License. The program has graphical user interface based on GTK+2 and supports quantum mechanical and molecular mechanic models, with geometry optimization, molecular dynamics, and a large set of visualization tools. Ghemical relies on external code to provide the quantum-mechanical calculations — MOPAC provides the semi-empirical MNDO, MINDO, AM1, and PM3 methods, and MPQC methods based on Hartree–Fock calculations.
Watcom C/C++ is an integrated development environment (IDE) product from Watcom International Corporation for the C, C++, and Fortran programming languages. Watcom C/C++ was a commercial product until it was discontinued, then released under the Sybase Open Watcom Public License as Open Watcom C/C++. It features tools for developing and debugging code for DOS, OS/2, and Windows, Linux operating systems, which are based upon 16-bit x86, 32-bit IA-32, or 64-bit x86-64 compatible processors.
MINDO, or Modified Intermediate Neglect of Differential Overlap is a semi-empirical method for the quantum calculation of molecular electronic structure in computational chemistry. It is based on the Intermediate Neglect of Differential Overlap (INDO) method of John Pople. It was developed by the group of Michael Dewar and was the original method in the MOPAC program. The method should actually be referred to as MINDO/3. It was later replaced by the MNDO method, which in turn was replaced by the PM3 and AM1 methods.
PQS is a general purpose quantum chemistry program. Its roots go back to the first ab initio gradient program developed in Professor Peter Pulay's group but now it is developed and distributed commercially by Parallel Quantum Solutions. There is a reduction in cost for academic users and a site license. Its strong points are geometry optimization, NMR chemical shift calculations, and large MP2 calculations, and high parallel efficiency on computing clusters. It includes many other capabilities including Density functional theory, the semiempirical methods, MINDO/3, MNDO, AM1 and PM3, Molecular mechanics using the SYBYL 5.0 Force Field, the quantum mechanics/molecular mechanics mixed method using the ONIOM method, natural bond orbital (NBO) analysis and COSMO solvation models. Recently, a highly efficient parallel CCSD(T) code for closed shell systems has been developed. This code includes many other post Hartree–Fock methods: MP2, MP3, MP4, CISD, CEPA, QCISD and so on.
In computational chemistry, NDDO is a formalism that was first introduced by John Pople; it is the basis for most semiempirical methods. While INDO added all one-centre two electron integrals to the CNDO/2 formalism, NDDO adds all two centre integrals for repulsion between a charge distribution on one centre and a charge distribution on another centre. Otherwise, the zero-differential overlap approximation is used. The common software program is MOPAC.
AMPAC is a general-purpose semiempirical quantum chemistry program. It is marketed by Semichem, Inc. and was developed originally by Michael Dewar and his group.
Spartan is a molecular modelling and computational chemistry application from Wavefunction. It contains code for molecular mechanics, semi-empirical methods, ab initio models, density functional models, post-Hartree–Fock models, and thermochemical recipes including G3(MP2) and T1. Quantum chemistry calculations in Spartan are powered by Q-Chem.
Semi-empirical quantum chemistry methods are based on the Hartree–Fock formalism, but make many approximations and obtain some parameters from empirical data. They are very important in computational chemistry for treating large molecules where the full Hartree–Fock method without the approximations is too expensive. The use of empirical parameters appears to allow some inclusion of electron correlation effects into the methods.
Materials Studio is software for simulating and modeling materials. It is developed and distributed by BIOVIA, a firm specializing in research software for computational chemistry, bioinformatics, cheminformatics, molecular dynamics simulation, and quantum mechanics.
CP2K is a freely available (GPL) quantum chemistry and solid state physics program package, written in Fortran 2008, to perform atomistic simulations of solid state, liquid, molecular, periodic, material, crystal, and biological systems. It provides a general framework for different methods: density functional theory (DFT) using a mixed Gaussian and plane waves approach (GPW) via LDA, GGA, MP2, or RPA levels of theory, classical pair and many-body potentials, semi-empirical and tight-binding Hamiltonians, as well as Quantum Mechanics/Molecular Mechanics (QM/MM) hybrid schemes relying on the Gaussian Expansion of the Electrostatic Potential (GEEP). The Gaussian and Augmented Plane Waves method (GAPW) as an extension of the GPW method allows for all-electron calculations. CP2K can do simulations of molecular dynamics, metadynamics, Monte Carlo, Ehrenfest dynamics, vibrational analysis, core level spectroscopy, energy minimization, and transition state optimization using NEB or dimer method.
Avogadro is a molecule editor and visualizer designed for cross-platform use in computational chemistry, molecular modeling, bioinformatics, materials science, and related areas. It is extensible via a plugin architecture.
DelPhi is a scientific application which calculates electrostatic potentials in and around macromolecules and the corresponding electrostatic energies. It incorporates the effects of ionic strength mediated screening by evaluating the Poisson-Boltzmann equation at a finite number of points within a three-dimensional grid box. DelPhi is commonly used in protein science to visualize variations in electrostatics along a protein or other macromolecular surface and to calculate the electrostatic components of various energies.