Ghemical

Ghemical is computational chemistry package, which is licensed under GNU GPL. Ghemical is implemented using the C++ programming language, and it has a graphical user interface which utilizes the OpenGL graphics interface and the GTK+ multiplatform widget library. Here are some features of the program:

Compute energy and gradient using :
quantum mechanical methods
Ab Initio methods provided by MPQC.
Semi-Empirical methods provided by MOPAC7.
molecular mechanics methods
all-atom MM methods (Tripos 5.2 + others).
coarse-grained MM for protein molecules [1] (work in progress).
optional distance constraints can be applied in MM calculations.
Options for studying a molecular system using :
Geometry Optimization.
Molecular Dynamics.

Conformational Searching :
Random Search.
Systematic Search.
Monte Carlo Search.

Other options for QM methods :
Stationary State Search.
Transition State Search.
Population Analysis.

Interfaces to external programs :
GAMESS.
Many file import/export features provided by OpenBabel.

OpenGL graphics presentations :
molecular graphics presentations :
Ball-And-Stick.
Van der Waals.
Cylinders.
Wireframe.
molecular editing tools :
add and remove atoms and bonds.
add or remove Hydrogens automatically.

sequence builder and identifier :
protein sequences.
nucleic acid sequences.

measurement tools for measuring :
distances.
angles.
torsions.

visualization options :
colored planes.
colored surfaces.
volume rendering.
protein ribbon models.

interactive graphing options :
Energy vs. torsion plot.
Energy vs. 2 torsions plot.
energy level diagram plot.
reaction coordinate plot.
"Project View" for viewing/editing the model and related information.
Text window for text-formatted output and logging, and a text command parser/interpreter.
Molecular Weight calculator.
MD Trajectory file viewer.

http://www.uku.fi/~thassine/projects/ghemical/