Charge-transfer-induced Frenkel exciton splitting in crystalline fullerene

Abstract
Temperature-dependent second-harmonic-generation (SHG) studies of excitons in crystalline fullerene are examined using theoretical estimates of the electrostatic energies of charge-transfer (CT) states. The observed Frenkel exciton splittings are interpreted in terms of indirect interactions mediated by the CT manifold. Model calculations reproduce the change in width of the SHG spectrum with temperature and rationalize its shape.