One can assume that the transition state for the exciton hopping possesses a structure in which all the anthracene moieties are equidistant to each other, as shown in Figure which corresponds to the ground state (S0) geometry. We thus computed the total energy (ETS0) of the T1 state at the S0 geometry using the DFT method, as shown in Figure . The reorganization energy (lT) for the conformation change to the T1-optimized geometry is obtained as follows, 𝜆 ( = 𝐸 ('< -𝐸 (MCU (8) where 𝐸 (MCU is the total energy of the optimized T1 geometry. From Figure and S17, 𝜆 ( = 0.21 eV is obtained. The agreement between 𝛥𝐻 ‡ = 0.23 eV and 𝜆 ( demonstrates that the pseudo-rotation in 3 TAB* originate from the activation motion to the S0 conformation where three anthracene components are equivalent taking on the C3 symmetry. The shorter exciton hopping time with 1/𝑘 LMC = 8 ps in 3 TAB* than the rotation in 3 DPA* because of the broader spectrum in Figure in the viscous media strongly supports that the motional narrowing is from the intramolecular exciton hopping. The positive activation entropy of 𝛥𝑆 ‡ = 0.45 meV K -1 represents the highly disordered conformation in the transition state. Asymmetric low-frequency vibration modes are likely to play an important role on the activation for the intramolecular exciton hops in the picoseconds time.