By default, symmetry point-groups are automatically assigned, and used in identifying the irreducible representations of molecular orbitals, vibrations, and states, and in accelerating the construction of the Hessian in FORCE calculations.

Sometimes a system almost has the symmetry of a point group higher than C_{1}. Minor deviations from exact symmetry are allowed, but these
sometimes cause difficulties. If that happens, then the job will fail. To prevent this happening, the symmetry can be re-defined as C_{1}. This effectively disables all the symmetry features, so some jobs, particularly ` FORCE` calculations, will take longer to run.

Use `NOSYM` if there is any reason to suspect that the point-group symmetry features are causing problems.

A second type of symmetry can be used by specifying ` SYMMETRY`.
This is distinct from the default of using the point-group of the system to
label irreducible representations and to accelerate