MODELING OF GEMINATE ANNIHILATION IN QUASI-ONE-DIMENSIONAL SOLIDS

Exciton migration processes in the liquid-crystal mesophase of phthalo cyanines and porphyrins exhibit extreme anisotropy, so a diffusion-bas ed analysis of the kinetics of annihilation may not be suitable, even if the appropriate three-dimensional diffusion tensor is used. A simul ation technique incorporating the crystal structure of a quasi-one-dim ensional phthalocyanine-like medium is developed and its predictions a re contrasted with those of the conventional diffusion-based treatment s. The kinetics obtained using the simulation model are very different from those given by conventional methods. For instance, the annihilat ion probability of a pair initially on the same stack is considerably larger. Approximate master-equation models for the annihilation kineti cs in highly anisotropic media are also described.