Vibrational relaxation beyond the linear damping limit in two-dimensional optical spectra of molecular aggregates

Abstract

We have implemented vibronic dynamics for simulations of the third order coherent response of electronic dimers. In the present communication we provide the full and detailed description of the dynamical model, recently used for simulations of chlorophyll-carotenoid dyads, terylene dimers, or hypericin. We allow for explicit vibronic level structure, by including selected vibrational modes into a "system". Bath dynamics include the Landau-Teller vibrational relaxation, electronic dephasing, and nonlinear vibronic (to bath) coupling. Simulations combine effects of transport and dephasing between vibronic levels. Transport is described by master equation within secular approximation, phase is accumulated in cumulants and its calculation follows the transport pathways during waiting time period.

Anharmonic Molecular Motion Drives Resonance Energy Transfer in peri-Arylene Dyads

“…What remains is to connect the microscopic parameterizations of the previous section to the vibronic dynamics of Perlík and Šanda (2017). To this end, we formally define excitonic states and energies by fixing H A(D) el at typical geometry R 0 .…”

“…The transition dipole dependencies on vibrational coordinates q A , q D are usually neglected in the Condon approximation. Details of the simulations, i.e., the quantum master equation to describe vibronic population transfer and second cumulants for line-shapes, were published previously (Perlík and Šanda, 2017). We also adopted correction factors , and 3 to connect absorption and fluorescence spectra, respectively, with the response functions along (Angulo et al, 2006).…”

“…In the present work, we use this vibronic approach (Perlík and Šanda, 2017) to unify the treatment of two peri-arylene dyads with parallel and orthogonal transition dipole moments of donor and acceptor, as depicted in Figure 1. The parallel arrangement leads to coupling strengths beyond the Förster limit, while the geometry of the orthogonal dyad suggests very weak interchromophoric coupling.…”

Geometric dependencies of vibronically mediated excitation transfer in rylene dyads

“…where d A j is displacement of j-th electronic surface. The dynamical modulation by other nuclear coordinates(including solvent) is represented by the quantity λ V (λ W ) and the relaxation rates Λ V (Λ W ) for linear (quadratic) vibration-to-bath coupling 27 , and λ A (Λ A ) for electronic dephasings. Parametrizing them by expanding the eigenspectrum Eq.…”

Annihilation Dynamics of Molecular Excitons Measured at a Single Perturbative Excitation Energy

“…The electronic model reproduces absorption, R 3 -2D (see the Supporting Information), and R 5 -2D spectra with good agreement. A possible, but computationally demanding, extension of the electronic model toward a vibronic description 40,41 is left for future research. Employing doublesided Feynman diagrams, we identified a single peak as a reporter of EEA.…”