The molecular orbitals that are primarily responsible for the CT character are illustrated in the middle part of Fig. , with arrows that represent the two dominant configurations in the wave function. The right side of FIG. : Percentage CT character for the S1, 1 ME, and 1 ME states in two different geometries of (PDI)2, called models 1 and 2 (or "MO" and "C8") in Fig. . The 1 ME state is defined to be higher-energy state of pair of ME states that emerge from the calculation.