# 1 Purpose

VIEWMOL is a graphical front end for computational chemistry programs. It is able to graphically aid in the generation of molecular structures for computations and to visualize their results. The program's capabilities include:

- Building and editing of molecules
- Visualization of the geometry of a molecule
- Tracing of a geometry optimization or a MD trajectory
- Animation of normal vibrations or to show them as arrows
- Drawing of IR, Raman, and inelastic neutron scattering spectra
- Drawing of an MO energy level or density of states diagram
- Drawing of basis functions, molecular orbitals, and electron densities
- Display of forces acting on each atom in a certain configuration
- Display of Miller planes in crystals
- Calculation of thermodynamic properties for molecules and reactions
- Drawings generated by VIEWMOL can be saved as TIFF, PNG, HPGL, or PostScript files
- Animations of normal modes can be converted to a video file (MPEG), e. g. for inclusion into World Wide Web documents (requires additional programs available on the Internet)
- Interface to the ray tracing program POVRAY (input file generation and use of POVRAY from within VIEWMOL)
- Input and output in a variety of formats, new formats can be added easily by the user

VIEWMOL includes a Python interpreter for automation.

At present VIEWMOL includes input filters for DISCOVER, DMOL3, GAMESS, GAUSSIAN 9X, GULP, MOPAC, PQS, TURBOMOLE, and Vamp outputs as well as for PDB files (VIEWMOL is therefore suited as a viewer for structural data on the World Wide Web). Structures can be saved as Accelrys' car-files, MDL files, and TURBOMOLE coordinate files. VIEWMOL can generate input files for GAUSSIAN 9X. VIEWMOL's file format has been added to OPENBABEL so that OPENBABEL can serve as an input as well as an output filter for coordinates.

VIEWMOL supports a space ball as input device.