THIS INFORMATION IS OBSOLETE AND IS PROVIDED ONLY FOR ITS HISTORICAL VALUE

by G. A. Kollmannsberger, Department of Chemistry, University of Konstanz, Konstanz, FRG

The performance of calculations on planar aromatic molecules which are either unstable or whose geometry has not yet been determined is often hindered by the fact that the supposed bond lengths and bond angles are not in accordance with the trivial constraint that a polygon representing an n-membered ring molecule must be closed. Since in most cases the stretching of a bond requires appreciably more energy than the deformation of an angle, the bond lengths are held fixed and only the bond angles are varied to get a closed polygon. The molecular symmetry can be taken into account by imposing conditions concerning the quality of certain angles. The solution angles are determined by the program within adjustable deviation intervals centered at the starting angles. An angle can be held fixed by putting the corresponding deviation interval equal to zero. The starting set of angles need not fulfill the sum rule for angles of a polygon. The maximal number of corners of a polygon has arbitrarily been fixed to N = 9. The program has an additional option. It is possible to minimize the RMS deviation of the actual bond angles from a set of angles considered as "optimal". This minimization requires additional runs where the final angles of the preceding run are to be taken as the starting angles for the following run.

FORTRAN IV (IBM 360/370) Lines of Code: 413 Recommended Citation: G. A. Kollmannsberger, QCPE 11, 287 (1975).