OPTICAL-ABSORPTION IN PAIRED CORRELATED RANDOM LATTICES

Optical absorption in a random one-dimensional lattice in the presence of paired correlated disorder is studied. The absorption line shape i s evaluated by solving the microscopic equations of motion of the Fren kel-exciton problem in the lattice. We find that paired correlation ca uses the occurrence of well-defined characteristic lines in the absorp tion spectra which clearly differ from the case of unpaired correlatio n. The behavior of the absorption lines as a function of defect concen tration is studied in detail. We also show how exciton dynamics can be inferred from experimental data by deriving an analytical expression relating the energy and intensity of lines to the model parameters.