Example: Carbon p²

SlaterDeterminants
C(p2) ALFA: s=1, px=py=2/3, pz=2/3; BETA: s=1, p=0 ! title
   S 1 // 1 ! irrep name and occupations
   P:x 0.666666666666666666 // 0 ! another irrep, et cetera
   P:y 0.666666666666666666 // 0
   P:z 0.666666666666666666 // 0
   D:z2 0 // 0
   D:x2-y2 0 // 0
   D:xy 0 // 0
   D:xz 0 // 0
   D:yz 0 // 0
SUBEND
C(p2) ALFA: S=1, px=py=1, pz=0; BETA: s=1 !next (Sl.Determinant) title
   S 1 // 1
   P:x 1 // 0
   P:y 1 // 0
   P:z 0 // 0
   D:z2 0 // 0
   D:x2-y2 0 // 0
   D:xy 0 // 0
   D:xz 0 // 0
   D:yz 0 // 0
SUBEND
C(p2) ALFA: s=1, px=py=0.5, pz=1; BETA: s=1
   S 1 // 1
   P:x 0.5 // 0
   P:y 0.5 // 0
   P:z 1 // 0
   D:z2 0 // 0
   D:x2-y2 0 // 0
   D:xy 0 // 0
   D:xz 0 // 0
   D:yz 0 // 0
SUBEND
C(p2) ALFA: s=1, px=py=0.5, pz=0; BETA: s=1, px=py=0, pz=1
   S 1 // 1
   P:x 0.5 // 0
   P:y 0.5 // 0
   P:z 0 // 1
   D:z2 0 // 0
   D:x2-y2 0 // 0
   D:xy 0 // 0
   D:xz 0 // 0
   D:yz 0 // 0
SUBEND
C(p2) ALFA: s=1, px=py=0.5, pz=0; BETA: s=1, px=py=0.5, pz=0
   S 1 // 1
   P:x 0.5 // 0.5
   P:y 0.5 // 0.5
   P:z 0 // 0
   D:z2 0 // 0
   D:x2-y2 0 // 0
   D:xy 0 // 0
   D:xz 0 // 0
   D:yz 0 // 0
SUBEND
C(p2) ALFA: s= 1, px=py=0, pz=1; BETA: s=1, px=py=0, pz=1 
   S 1 // 1
   P:x 0 // 0
   P:y 0 // 0
   P:z 1 // 1
   D:z2 0 // 0
   D:x2-y2 0 // 0
   D:xy 0 // 0
   D:xz 0 // 0
   D:yz 0 // 0
SUBEND

In the example the AOC calculation is the Carbon atom in spherical symmetry (symmetry name atom).

Several spin states can be generated from this AOC set of orbitals, but they all have a lower symmetry than the AOC. In the example the point group D_∞h (DLIN) could be used in the SLATERDETERMINANTS calculation. In D_∞h the p orbitals split into two sets, p_x and p_y occur in π_x and π_y respectively, so their occupations must be identical, and p_z is a Σ_u orbital.

In the data block of the SLATERDETERMINANTS key (or in the file) we now specify the occupations for the subspecies of the atom irreps of a specific Slater determinant and the program will sort out the corresponding occupations in the d(lin) symmetry.

In all cases the orbitals used for the energy calculation(s) will be the self-consistent AOC orbitals.

In the given example, the first set of occupations does not correspond to a Slater determinant, but is the spin-polarized spherical case with the p electrons evenly distributed over all components.