Similarly, the T+D activation motions to weaken the exchange-coupling also produce the anisotropic D-Q interactions for the spin polarization. However, it is also anticipated that the two middle quartet sublevels of 4 (T+D)1/2 and 4 (T+D)-1/2 are almost degenerated with the doublets of 2 (T+D)1/2 and 2 (T+D)-1/2, respectively (Fig. right), so that D ±"/$ -Q ±"/$ interconversions are preferential during the activation time to result in the isotropic quartet sublevel populations in Q ±"/$ . The absence of the outer E/A/E/A polarization 15 in the phenylene linked system of PDI-ph-trityl strongly indicates that the T+D activation is suppressed in the D ±"/$ -Q ±"/$ interconversions.