Note

This website is presently under development. The primary website for MOPAC is still http://openmopac.net until the majority of its contents have been migrated here.

AUTOSYM

Automatically detects and imposes a subset of the coordinate constraints available with the SYMMETRY keyword. Specifically, the type 1, 2, 3, and 14 Z-matrix constraints are applied to bond lengths that are within \(0.0001 \AA\) and bond or dihedral angles that are within \(0.0057^\circ\). Constraints are not applied to unoptimized coordinates whose optimization flags are set to 0.

When the AUTOSYM keyword is used, the tail of the .arc file includes a list of coordinate constraints that can be used by an input file if the AUTOSYM keyword is replaced by the SYMMETRY keyword.