Exciton Coherence Length Fluctuations in Chromophore Aggregates Probed by Multidimensional Optical Spectroscopy
2010
Abstract
The coherent third order optical response of molecular aggregates with fluctuating frequencies, couplings, and transition dipole moments. We derived stochastic nonlinear exciton equations (by combining the quasiparticle picture of excitons with the path integral over stochastic bath paths) and calculated coherent 2D spectra for a tetramer model system whose transition dipole orientations undergo stochastic jumps on an arbitrary timescale.
Signatures of domain coherence length fluctuations are observed in the cross peak dynamics in specific pulse polarization configurations.