ABSTRACT
The linear spectroscopic signal is fully characterized by the associated linear response function and provides information on optical transition frequencies, transition amplitudes such as dipole strength, light-scattering cross-section, and so forth, as well as chromophore-bath interaction-induced line broadenings. If two different chromophores are spatially close to each other, quantum states of the two chromophores cannot be written as simple product states and become delocalized over the two chromophores due to finite couplings. Such coupling-induced effects, such as mode mixing, excitation transfer processes and so forth are however quite weak so that their signatures and characteristc features in a typical 1D spectrum are often completely hidden under the primary spectroscopy properties.1 As demonstrated over the last decade, this spectral congestion and masking problem can be partly overcome by using 2D spectroscopic methods.
