Time-resolved spectroscopy provides the main tool for analyzing the dynamics
of excitonic energy transfer in light-harvesting complexes. To infer
time-scales and effective coupling parameters from experimental data requires
to develop numerical exact theoretical models. The finite duration of the
laser-molecule interactions and the reorganization process during the exciton
migration affect the location and strength of spectroscopic signals. We show
that the non-perturbative hierarchical equations of motion (HEOM) method
captures these processes in a model exciton system, including the charge
transfer state
