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512. STRUCTURE: Rapid Interactive Structure Input and
Geometry Optimization
by Martin Saunders and Ronald M. Jarret, Sterling Chemistry Laboratories, Yale University, New Haven, Connecticut 06511 This program rapidly determines Cartesian coordinates for all atoms in a molecule. It uses directions of successive bonds (up, down, in, out, left, right) between (non-hydrogen) atoms to establish atomic positions and generate these coordinates. Hydrogen atoms and lone electron pairs are attached to carbon, oxygen, nitrogen, and silicon atoms automatically by STRFIT. Initially entered structures are geometrically optimized by an essentially pure Central Force-Field approach; that is, only distances (1-2, 1-3, 1-4, 1-5, etc.) are considered during structural refinement to a geometry of minimal force. STRFIT is currently designed to produce output suitable for Allinger's MM2 program (as found in the Operating Instructions for MM2 and MMP2 Programs 1977 Force Field, updated as of January, 1980, p. 42, by N. L. Allinger and Y. H. Yuh). STRFIT can greatly facilitate molecular mechanics calculations by allowing extremely rapid structure input and swift geometry optimization. A file is also generated that is designed for use with the graphics programs: SCOPE and PRINTER. These programs allow for viewing and rotating the entire molecule (as a ball and stick display) about the X, Y and Z axis on the screen of any standard terminal and get a high-resolution hard copy with perspective on a PRINTRONIX or EPSON dot-matrix printer. FORTRAN 77 (VAX) Lines of Code: 2300 |