Manipulation of two-dimensional spectra of excitonically coupled molecules by narrow-bandwidth laser pulses

Complete expressions within the response function theory are derived for a coherent two-dimensional (2D) signal covering the finite-bandwidth and pulse-overlap effects. Ideal time domain, frequency domain as well as mixed regime are considered. Conditions for the strong pulse-overlap effects are also described and analyzed. As demonstrated for the excitonically coupled dimer, certain configurations of central frequencies allow to extract various peaks in the 2D signal, resembling certain physical processes. In the case of weakly overlapping pulses, the scheme for generating both ultra-broad-bandwidth time-domain signal and frequency-domain spectra from a set of narrow-bandwidth multi-color measurements is presented. Possibility of reconstructing microscopic parameters such as inter-molecular couplings and transition dipole orientations from high-resolution crosspeaks is discussed. (C) 2010 Elsevier B. V. All rights reserved.