Fortran 90 code by Paul Stevenson.

Package of molecular simulation programs in Fortran 77 and C, distributed subject to a licensing agreement.

Performs general ab initio electronic structure calculations within the framework of MR-CISD and related methods including size-extensivity corrections.

Links to MECHMOD, software aid to the development of reaction mechanisms, and KINAL/KINALC, programs for the simulation and analysis of general mass action kinetics reaction mechanisms.

ICON-EDiT is a program package that performs extended-Hückel molecular orbital and oscillator strength calculations on molecules. The complete program package can be downloaded, along with examples and a manual. BICON-CEDiT performs extended-Hückel crystal orbital and oscillator strength calculations on solids. The complete program package can be downloaded, along with examples a manual, and k-point sets.

Archive of Fortran codes.

Calculates molecular properties with SCF, MP2, MCSCF or CC wave functions. The strengths of the program are mainly in the areas of magnetic and (frequency-dependent) electric properties, and for studies of molecular potential energy surfaces, both for static and dynamical investigations.

Computes numerical solutions to the Poisson-Boltzmann equation (both linear and nonlinear form) for molecules of arbitrary shape and charge distribution.

Fortran (and a bit of C) code for relativistic molecular calculations based on the Dirac-Coulomb Hamiltonian. Free for academic use.

Calculates low-energy conformations of polypeptides and proteins, compatible with distance and dihedral angle constraints obtained typically from NMR experiments. Free for academics.

Links to free software, primarily Fortran, for atomic scale simulations, including the topics of Molecular Dynamics/Force Fields, Tight binding, Quantum Chemistry: Hartree Fock/MP/CC/CI, Density Functional Pseudopotential/Pseudoprojector generators, Quantum Monte Carlo, and Many-Body Perturbation Theory (GW, Bethe-Salpether).

Predicts the energies, molecular structures, and vibrational frequencies of molecular systems, along with numerous molecular properties derived from these basic computation types. It can be used to study molecules and reactions under a wide range of conditions, including both stable species and compounds which are difficult or impossible to observe experimentally such as short-lived intermediates and transition structures. [Commercial]

Fortran 90 program by Andy Stone to carry out Distributed Multipole Analysis of wavefunctions calculated by the Gaussian system of programs, using the formatted checkpoint files that they produce. The result is a set of multipole moments at sites defined by the user (usually at the positions of the atomic nuclei) which, given an accurate wavefunction, provide an accurate description of the electrostatic field of the molecule. It is very fast, typically requiring only a few seconds of cpu time.

F (Fortran 95 subset) program by Bob Charity to calculate the decay of a compound nucleus via the statistical model.

General ab-initio quantum chemistry package.

Fortran 90 program by Natalie Holzwarth to calculate the electronic energy and density for an atom using density functional theory. For a specified atomic configuration, the optimal electronic wavefuncitions are calculated numerically. Designed for student use.

General purpose molecular dynamics Fortran 77 code for simulations of mixtures of either rigid or flexible molecules, interacting by AMBER-like force field in a periodic rectangular cell. In the case of flexible molecules the double time step algorithm is used.

Ab-initio Fortran 90 programs for molecular electronic structure calculations, designed and maintained by H.-J. Werner and P.?J. Knowles.

Fortran 77 program to compute charges, bond types, hybrid directions, resonance weights, bond orders and other familiar valence descriptors. [Commercial]

Computes the properties of molecular and periodic systems using standard quantum mechanical descriptions of the electronic wavefunction or density. In addition, NWChem has the capability to perform classical molecular dynamics and free energy simulations. In order to obtain NWChem, you must be a permanent faculty or staff member of the facility or institution you are associated with.

Fortran 77 program for drawing crystal structure illustrations. Ball-and-stick type illustrations of a quality suitable for publication are produced with either spheres or thermal-motion probability ellipsoids, derived from anisotropic temperature factor parameters, on the atomic sites. The program also produces stereoscopic pairs of illustrations which aid in the visualization of complex arrangements of atoms and their correlated thermal motion patterns.

Package of Fortran 77 programs to compute phase angles for diffraction data from macromolecular crystals.

Computes the total energy absorption cross section for the photodissociation of a diatomic molecule using Time-Dependent Quantum Dynamics.

by David Cappelletti.

By the research group of Professor George Schatz.

By N. Sathyamurthy.

The program atompaw generates projector and basis functions which are needed for performing electronic structure calculations based on the projector augmented wave (PAW) method. The pwpaw code is a plane wave implementation of the PAW method developed by Blochl for electronic structure calculations within the framework of density functional theory. By Natalie Holzwarth.

Most programs are in Fortran.

Codes by Kieran Lim for chemical dynamics, a vibrationally adiabatic impulsive dissociation model, Huckel orbital theory, calculation of gas-kinetic collision rate coefficients, and Monte Carlo quasiclassical trajectory simulation.

Quantum Monte Carlo code, available on request, to solve the electronic, non-relativistic, clamped-nuclei Schrödinger equation. The current version performs variational Monte Carlo (VMC) and fixed-node diffusion Monte Carlo (DMC) computations of the energy and other properties of atoms and molecules.

Fortran code and documentation from the textbook by Jack Simons and Jeff Nichols.

Program by Anthony Stone and Charles Wood intended primarily for the calculation of Wigner 3j, 6j and 9j symbols, which occur in the theory of angular momentum, and for performing elementary arithmetic with them.

Fortran 77 program to calculate the kinematics for complex fragments emitted in fusion-like reactions.

By Paul Stevenson, in Fortran 90.

Codes from course by Eduardo Gómez Maqueo for studying the dependence of the solution of an equation on a parameter, ODE integration by Michelsen's method, COLSYS (spline collocation at Gaussian points using a B-spline basis), finite differences (Numerov's methods), orthogonal collocation, and finite elements.

Complete and general package for molecular mechanics and dynamics, with some special features for biopolymers.

Free package for doing theoretical chemistry calculations. Fortran 95 source files and the "foo" files used to generate them are provided. Foo is an object-oriented language created by the authors of the package.

Fortran 90 program by Burkhard Schmidt and collaborators to study quantum-mechanical and quantum-classical wavepacket propagation.

Fortran 90 code to perform electronic structure calculations of solids using density functional theory (DFT). It is based on the full-potential (linearized) augmented plane-wave ((L)APW) + local orbitals (lo) method, among the most accurate schemes for band structure calculations. [Commercial]