Q-Chem 4.3 User’s Manual

3.24 Geometry Optimization with General Constraints ($opt)

When a user defines the JOBTYPE to be a molecular geometry optimization, Q-Chem scans the input deck for the $opt keyword. Distance, angle, dihedral and out-of-plane bend constraints imposed on any atom declared by the user in this section, are then imposed on the optimization procedure. See Chapter 9 for details.