Ghemical is a molecular modelling package with GUI and 3D-visualization tools.
Ghemical project has a graphical user interface (which is based on GNOME), and it supports both quantum-mechanics (semi-empirical and ab initio) models and molecular mechanics models (there is an experimental Tripos 5.2-like force field for organic molecu Also a tool for reduced protein models  is included. Geometry optimization, molecular dynamics and a large set of visualization tools are currently available.
Ghemical relies on external code to provide the quantum-mechanical calculations. Semi-empirical methods MNDO, MINDO/3, AM1 and PM3 come from the MOPAC7 package (Public Domain), and are included in the source distribution.
The MPQC package (GNU GPL) is used to provide ab initio methods: the methods based on Hartree-Fock theory are currently supported with basis sets ranging from STO-3G to 6-31G**.
The MPQC code is not included in the source distribution. In order to use the MPQC-based ab initio methods in Ghemical, you must first compile and install the MPQC program for your system, and then compile Ghemical using some specific settings that link the programs together; see the INSTALL file for more information. Ghemical also contains the OpenBabel package for import and export of many different file formats (as well as other tasks).
Once you have downloaded the latest release, you should extract all files from your archive file using "tar -zxvvf ghemical-1.00.tgz" or equivalently "gunzip ghemical-1.00.tgz; tar -xvvf ghemical-1.00.tar". After that please read the "INSTALL"-file you just extracted to get additional information.
What's New in This Release:
Â· Ghemical is now heading towards a new stable release.
Â· The current release is the recommended version for "production" use.
Â· It's not an official stable release because of the newly added Win32 port, which still needs some finishing touches before everything works.