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625. EHGO: Extended-Hückel-Based Geometry Optimizing
Program
by Kenneth J. Tupper, QCPE, Indiana University, Bloomington, IN 47405 This program is based on the Extended Hückel system developed by R. Hoffman et al. known as FORTICON8 (QCPE 344). To this system were added the nuclear repulsion work done by A. Anderson and the line optimizer contained in the program CINMIN (QCPE 389) by M. Fraser and D. M. Hayes. The major change which differentiates this system from its predecessors is that the Slater coefficients on functions which are used in these calculations are treated as optimizable parameters.Without the inclusion of this change, geometry optimization with Extended Hückel is not successful. As the system now exists, it contains parameters for elements C, N, O and H and is currently dimensioned to handle 50 atoms. With the speeds at which the system can operate at this level of approximation, it could be expanded to do calculations on systems containing 500 atoms and yield structural information on molecules of biological interest. Lines of Code: 5000 FORTRAN 77 (VAX) |