The effects of orientational and energetic disorder on Forster energy migration along a one-dimensional lattice

Numerical simulations of exciton migration along a one-dimensional lattice via Forster energy transfer are reported. The roles of static Gaussian energetic disorder and transition dipole orientational disorder are investigated. Both disorder mechanisms result in subdiffusive behavior during the initial phase of energy migration, tending asymptotically to normal diffusion. The dependence of the subdiffusion parameters on the inhomogeneous linewidth and intersite spacing is examined. Depending on the exciton lifetime, subdiffusive motion may dominate the exciton displacement behavior, and it becomes problematic to use normal diffusion theory to make even qualitative predictions about the exciton motion.