The effect of this keyword is to set to zero coefficients in unwanted
For this purpose the symmetry group defined for the CASSCF wavefunction
is used (always a subgroup of D).
The list of irreps in the command specifies which components
of the wavefunction should be kept.
If no irreducible representations are given, the current
wavefunction symmetry is assumed. In a state-averaged calculation,
all irreps are retained for which a non-zero weight has been specified in the
The SYMPROJ keyword may also be used in combination with constraints.