SYMMETRY Section

The SYMMETRY section controls point-group detection and symmetry usage.

Keywords

KeywordTypeDefaultDescription
Tolerancefloat1e-3Tolerance for point-group detection (Å)
DisablebooleanfalseForce C1 symmetry

Examples

Default symmetry detection:

SYMMETRY
  Tolerance  0.001
END

Tighter symmetry tolerance:

SYMMETRY
  Tolerance  0.0001
END

Disable symmetry (force C1):

SYMMETRY
  Disable  true
END

Notes

  • Symmetry is enabled by default. The detected point group is printed in the job header and used to skip symmetry-equivalent ERI shell quartets during energy, gradient, and Hessian computations.
  • Disable true forces C1 symmetry: integrals are computed without point-group screening, and all orbital labels are printed as A.
  • The 8-fold permutational symmetry of ERIs is always applied regardless of symmetry settings.
  • The symmetry tolerance controls how strictly the geometry must match the point group symmetry elements.