Inspecting molecular aggregate quadratic vibronic coupling effects using squeezed coherent states
arXiv:2306.00436 · doi:10.1039/D2CP04212F
Abstract
We present systematic comparison of three quantum mechanical approaches describing excitation dynamics in molecular complexes using the Time-Dependent variational principle (TDVP) with three increasing sophistication trial wavefunctions (ansatze): Davydov D2 , squeezed D2 (sqD2) and a numerically exact multiple D2 (mD2) ansatz in order to characterize validity of the sqD2 ansatze. Numerical simulation of molecular aggregate absorption and fluorescence spectra with intra- and intermolecular vibrational modes, including quadratic electron-vibrational (vibronic) coupling term, which is due to vibrational frequency shift upon pigment excitation is presented. Simulated absorption and fluorescence spectra of J type molecular dimer with high frequency intramolecular vibrational modes obtained with D2 and sqD2 ansatze matches spectra of mD2 ansatz only in the single pigment model without quadratic vibronic coupling. In general, the use of mD2 ansatz is required to model accurate dimer and larger aggregate's spectra. For a J dimer aggregate coupled to a low frequency intermolecular phonon bath, absorption and fluorescence spectra are qualitatively similar using all three ansatze. The quadratic vibronic coupling term in both absorption and fluorescence spectra manifests itself as a lineshape peak amplitude redistribution, static frequency shift and an additional shift, which is temperature dependent. Overall, the squeezed D2 model does not result in considerable improvement of simulation results compared to the simplest Davydov D2 approach.
References in corpus (12)
- Vibronic origin of long-lived coherence in an artificial molecular light harvester
- Fast, accurate simulation of polaron dynamics and multidimensional spectroscopy by multiple Davydov trial states
- Variational dynamics of the sub-Ohmic spin-boson model on the basis of multiple Davydov states
- Dynamics of Davydov Ansatze
- Finite-temperature time-dependent variation with multiple Davydov states
- Apoptosis of moving, non-orthogonal basis functions in many-particle quantum dynamics
- Exciton localization in tubular molecular aggregates: size effects and optical response
- Proton Tunneling in a Two-Dimensional Potential Energy Surface with a Non-linear System-Bath Interaction: Thermal Suppression of Reaction Rate
- Modeling Molecular J and H Aggregates using Multiple-Davydov D2 Ansatz
- Vibrational damping effects on electronic energy relaxation in molecular aggregates
- Modeling Non-Reversible Molecular Internal Conversion Using the Time-dependent Variational Approach with sD2 Ansatz
- Simulation of ab initio optical absorption spectrum of β-carotene with fully resolved S_{0} and S_{2} vibrational normal modes