Temperature effects on singlet fission dynamics mediated by a conical intersection

Abstract

Note: This paper is part of the JCP Special Topic on Excitons: Energetics and Spatio Temporal Dynamics.

Exciton Transfer in Organic Photovoltaic Cells: A Role of Local and Nonlocal Electron-Phonon Interactions in a Donor Domain

“…The off-diagonal elements representing the interaction between the ground and excited state are ∆ 12 = ∆ 21 = 0.32ω. It should be noted that, while similar single crystals, which include rubrene 52,53 and pentacene 54 have been modeled and investigated, the parameter values of the offdiagonal element of tetracene has not been well explored. Here we employ the value of pentacene as a representative case, while the interactions between the excited states are chosen to be ∆ 23 = ∆ 32 = 1.23ω for the pair 1 and ∆ 23 = ∆ 32 = 0.12ω for the pair 2, respectively.…”

Excitons: Energetics and spatio-temporal dynamics

“…A small CT admixture can lead to an enhancement of low electronic coupling for singlet fission, while large CT components have also been found to play an important role in the spectra of crystals, aggregates, and light-harvesting complexes in photosynthetic apparatuses. Long-range corrected (LC) DFT is a good compromise for charge transfer characteristics, as illustrated in the tests of LC-DFTB by Darghouth et al 18 Other discussions on the CT components are seen in the works by Sun el al., 19 Balooch Qarai et al, 20 and others. 6,13,14,21 With electronic states obtained, Tölle et al 22 show how diabatic states can be defined and calculated, from which an excitonic model Hamiltonian can be built.…”

“…14,22 Various contributions in this Special Topic collection illustrate the flexibility and quantitative performance of vibronic exciton models that can be constructed from such multi-state descriptions. 19,20,24,25…”

“…Di Maiolo et al 25 show the promise of the ML-MCTDH method as a full quantum propagation scheme for hundreds of electronic states and vibrational modes, which is applied to coherent intra-chain exciton migration and the computation of temperature-dependent diffusion coefficients. Sun et al 19 employ a variational, multiconfigurational Davydov approach to probe the temperature dependence of singlet fission. Mixed quantum-classical nonadiabatic quantum dynamics approaches based on the QCLE are addressed by Kim and Rhee; 37 these can potentially be generalized for a large class of molecular systems but rely on certain kinds of approximations that become reasonable in the semiclassical or classical limits of nuclear degrees of freedom.…”

The hierarchy of Davydov's Ansätze and its applications

“…The method of displaced number states with the multi-D 2 Ansatz can provide efficient, quantitative descriptions of nonadiabatic dynamics at conical intersections in chemical reactions and beyond. 51,52 Based on many-body wave functions, the multiple Davydov Ansatz method is nonperturbative and numerically exact if provided sufficiently large multiplicities of the trial states, capable to compute nonlinear spectroscopic responses for close comparisons with experiment as will be elaborated in the next section. 52,127…”