Interrupted coarse-grained theory of unimolecular relaxation and stimulated recurrences in photoexcitation of a quasicontinuum

Abstract

We present an approximate analytic theory of photoexcitation of a quasicontinuum. The theory accounts for unimolecular dipole dephasing relaxation and partial dipole recorrelations. It is based on systematic repeated interruption of coarse-grained dynamical evolution of the system’s wave function. We predict sign reversals and discontinuities in transition rates, and other quasiperiodic phenomena. The theory gives fair agreement with computer simulations and reproduces features of two known exactly soluble models.