EFFECTS OF DIPOLE-DIPOLE INTERACTION OF CHARGE-TRANSFER EXCITONS AND THEIR MANIFESTATION IN TRANSIENT GRATING PHENOMENA

We show that the interaction of charge-transfer excitons (CTEs) may ha ve a strong influence on their kinetics and may manifest itself in non linear optics. For CTEs in molecular multilayer structures, even at ro om temperature and a relatively low (less than or similar to 0.05%) co ncentration of CTEs, this interaction results, e.g., in an appreciable renormalization of both the diffusion coefficient of CTEs and the dec ay rate of transient gratings, as well as in the generation of higher spatial harmonics of the initial grating of the CTE density. These eff ects increase considerably with decreasing temperature.