ADF
   ADF, the Amsterdam Density Functional program for the treatment of complex chemical problems.
   http://www.scm.com

AOMix
   A program for molecular orbital analysis. It calculates the MO compositions of the constituent chemical fragments from the output files of various quantum-chemical packages, analyzes chemical bonding using overlap populations, and generates density-of-sta
   http://www.sg-chem.net/

ArgusLab
   A free molecular modeling program for Windows9x operating systems with 3D-builder, various ab initio calculation modules and simple molecular mechanics.
   http://www.planaria-software.com/

Atoms in Molecules (AIM2000)
   Windows program for analyzing and visualizing molecules using the theory of Richard Bader. Demo version available.
   http://www.aim2000.de

Banned By Gaussian
   Site critical of Gaussian, Inc.'s licensing practices. Reports allegations of Gaussian banning "competitors" from using their product.
   http://www.bannedbygaussian.org/

CASTEP - CAmbridge Serial Total Energy Package
   Uses density functional theory to provide an atomic-level description of materials and molecules.
   http://www.tcm.phy.cam.ac.uk/castep/

CHEAQS
   Free windows program for calculating chemical equilibria in aquatic systems. CHEAQS solves speciation problems and includes a customizable database of equilibrium constants.
   http://home.tiscali.nl/cheaqs

CHEMKED
   Chemical kinetics of gas phase reactions. Databases, simulation, and analysis software for Windows. Demo version available.
   http://mark.jelezniak.de/Chemked/

CHEMKIN Collection Software
   Simulates complex chemical kinetics in reacting flow.
   http://www.chemkin.com/

CONFLEX2000
   Commercial conformational searching and analysis tools for Linux, Mac OS X, and Windows. Compatible w/CAChe, ChemOffice, and Amber. Screen shots, data sheet, ordering, and trial versions available.
   http://www.conflex.us/

CRYSTAL Home Page
   Unix program to compute the electronic structure of periodic systems within Hartree Fock, density functional or various hybrid approximations. Documentation, licensing, and downloads available.
   http://www.crystal.unito.it/

Environment-Dependent Interatomic Potential (EDIP)
   Codes in C and Fortran by Martin Z. Bazant to model interatomic forces in covalent solids and liquids which incorporates recent theoretical advances in understanding the environment-dependence of (sigma) chemical bonding in condensed phases.
   http://www-math.mit.edu/~bazant/EDIP/

Extensible Computational Chemistry Environment
   Graphical user interface for Linux/Solaris/IRIX with visualization tools and a data management framework for setting up, submitting, and analyzing computational chemistry calculations.
   http://ecce.emsl.pnl.gov/

GAMESS-UK
   Free program derived from the original GAMESS code.
   http://www.cse.clrc.ac.uk/qcg/gamess-uk/

Gamess
   An ab initio quantum chemistry package GAMESS. Developed by the Mark Gordon research group at Iowa State University. Site is not GAMESS-Uk.
   http://www.msg.ameslab.gov/GAMESS/GAMESS.html

GaussSum
   Collection of Python scripts which parse the output of Gaussian or GAMESS calculations to extract information such as the progress of the SCF cycles, geometry optimisation, UV-Vis/IR/Raman spectra, MO levels, and MO contributions.
   http://gausssum.sourceforge.net/

Jaguar
   A general purpose ab initio electronic structure package that is capable of computing variety of properties based on various uncorrelated and correlated wavefunctions.
   http://www.schrodinger.com/Products/jaguar.html

MOLCAS
   Program for an accurate ab initio treatment of very general electronic structure problems for molecular systems in both ground and excited states. Online manuals, billboard and patches for MOLCAS.
   http://www.teokem.lu.se/molcas/

MOMix and ALP-Vibro
   Programs for Quantum Chemistry. MOMix (electron population analysis). ALP-vibro (animation of molecular vibrations). Spectrum Wizard.
   http://www.chem.yorku.ca/grad/SG/momix.htm

MPQC
   The "Massively Parallel Quantum Chemistry Program". Computes properties of atoms and molecules from first principles using the time independent Schrödinger equation. Free, available under the GPL.
   http://www.mpqc.org/

Moloc
   Molecular Design Software Suite for Irix, Linux, and Windows. Includes features such as structure generation, molecular mechanics, conformational search, molecular dynamics, and similarity analysis. Free for academic users.
   http://www.moloc.ch/

Motofit
   Co-refines Neutron and X-ray reflectometry data, using Parratt recursion and least squares fitting. It works in the IGOR Pro environment (TM Wavemetrics).
   http://motofit.sourceforge.net

ORCA
   Ab initio, DFT and semiempirical SCF-MO package, with specific emphasis on spectroscopic properties of open-shell molecules. Free binaries for academic users are available for a variety of platforms.
   http://ewww.mpi-muelheim.mpg.de/bac/logins/downloads_en.php

PyQuante
   "Python Quantum Chemistry" - an open-source suite of programs for developing quantum chemistry methods. Emphasis is on simplicity, rather than speed, but some bottlenecks are written in C.
   http://pyquante.sourceforge.net/

SHB_interactions
   Free program based on Extended Hückel calculations and Mulliken overlap populations for measuring the strength of hydrogen bonds and other intermolecular interactions in drug-biopolimer complexes.
   http://gw-chimie.math.unibuc.ro/staff/cbendic/shb/shb_interactions.html

Spectra
   Windows program for the interactive analysis of crystal field spectra of f-block elements.
   http://chemistry.anl.gov/downloads/spectra/

WebMO
   Web interface for the quantum chemistry packages MOPAC, Gaussian, and GAMESS. Free version available for download; pro version also available.
   http://www.webmo.net/

WinMopac
   Free graphical version of MOPAC 7 for windows, with an integrated molecular viewer (RasWin). Used for semiempirical molecular orbital calculations with the MNDO, AM1, and PM3 methods.
   http://www.psu.ru/science/soft/winmopac/index_e.html

YAeHMOP
   "Yet Another extended Huckel Molecular Orbital Package". Performs calculations and visualization for both molecular and extended materials in 1, 2, or 3 dimensions. Freely available in source form.
   http://yaehmop.sourceforge.net/

Zeta Potential
   Zeta is a free (GPL) computer program which can be used to calculate the zeta potentials.
   http://zeta-potential.sourceforge.net/

Zori
   Open source quantum chemistry program for atoms and molecules using the quantum Monte Carlo method.
   http://www.zori-code.com/