Excitation dynamics of two level quantum systems coupled to Morse vibrations

Abstract

Electronic excited states of a molecular aggregate coupled to Morse vibrations are analysed by a nonperturbative time dependent variational approach. General equations of motion for an electronically excited state are derived for electronic amplitudes, nuclear displacements and squeezing of the nuclear wave packets. Numerical simulations demonstrate that anharmonicities of vibrations lead to short-term irreversible dynamics, extra localization and transformation of stationary lowest-energy states.