Fig. 5. (a) Coulombic coupling (J_Coul) for four representative acene dimers (two linear and two non-linear acenes) with varying α and d_i. (b) The effect of short-range excitonic coupling (J_CT ∝ −t_et_h) as a function of rotational angle (α) in dimeric acenes (d_i = 4 Å).