***,N2
geometry={N1;N2,N1,r}                 !geometry input
r=2.2                                 !bond length
{hf;occ,3,1,1,,2;wf,14,1;save,2100.2} !scf calculation

{multi;occ,3,1,1,,3,1,1;              !Define occupied orbitals
frozen,1,,,,1,2100.2;                   !Define frozen core scf orbitals
config;                               !Use CSF method
wf,14,1;                              !Define state symmetry
restrict,0,2,3.5,1.6,1.7;             !Restriction to singles and doubles
restrict,-1,-1,3.5,1.6,1.7;           !Take out singles
print,ref1                            !Print configurations
natorb,ci,print}                      !Print natural orbitals and CI coeffs