W0026

CrystMol 2.0 – Personal Computer Software for Analysis and Manipulation of Crystal Structures. David J. Duchamp, Kalamazoo, MI 49009-9159.

CrystMol 2.0, containing many new and improved features, is in final development, and will be released soon in Macintosh and Windows versions. CrystMol 1.0 substantially met its design goal of providing a low-cost personal computer software package, useful as both a teaching and research tool, focused on crystal structures, and capable of display, analysis, and manipulation of a wide range of structural types and sizes. CrystMol provides interactive rotation, translation, zooming, and clipping of structures drawn in a variety of display styles including: line, stick, ball, ball & stick, thermal ellipsoid, space filling, and various combinations of these. Space group symmetry is built in. Symmetry-related units may be easily added and deleted, facilitating the study of symmetry and crystal packing. Other facilities include an electronic notebook, user libraries of structures, support for disordered structures, and three-dimensional building and editing of structures. Standard metrics with standard deviations are available, including: bond distances, bond angles, torsion angles, non-bonded distances, hydrogen bonds, and best planes. CrystMol supports structure input by several means, including both small molecule and macromolecular versions of the Crystallographic Information File (CIF).

In CrystMol 2.0, the display software was rewritten using OpenGL, the current industry standard for three-dimensional display. For macromolecular work, ribbon drawings are now available, and an algorithm was designed and developed for defining secondary structure (helices and sheets) from atomic positions. For teaching use, a facility for making QuickTime movies has been added, as well as the ability to save still images in a wide variety of file formats suitable for presentation or web use. A new companion molecular mechanics application, CrystMolMM, was developed with CrystMol providing the user interface. With capability for both gas phase and in-crystal calculations, CrystMolMM builds upon previous molecular mechanics work by the author.

The presentation will review CrystMol basics, and discuss new features added in current development. CrystMol development has been strongly influenced by feedback from original beta testers and comments at ACA Meetings. The author continues to welcome any and all suggestions on how to make CrystMol more useful in research and teaching.