Figure : Active natural orbitals and the corresponding occupation numbers from the (36e,2h,2e; 16o,5o,13o) restricted active space for the S 0 state of the bare copper corrole on its XMS-CASPT2 optimized geometry. Although this molecule does not have C 2V symmetry due to its saddled structure, the orbitals are labeled as they would be in the planar geometry.