Vibronic effects and destruction of exciton coherence in optical spectra of J-aggregates: A variational polaron transformation approach

Bloemsma, Erik A.; Silvis, Maurits H.; Stradomska, Anna; Knoester, Jasper

doi:10.1016/j.chemphys.2016.06.018

Cited by 8 publications

(13 citation statements)

References 79 publications

(99 reference statements)

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“…[40], and more recently in Ref. [48], these kinds of variational canonical transformation methods could offer an accurate description of both static properties (e.g., the ground state, the optical spectra, etc.) and dynamical properties (e.g., the exciton transport mechanisms) from intermediate to strong exciton-vibration coupling regimes.…”

Section: B the Generalized Merrifield Transformationmentioning

confidence: 96%

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When polarons meet polaritons: Exciton-vibration interactions in organic molecules strongly coupled to confined light fields

Feist

García‐Vidal

2016

Phys. Rev. B

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We present a microscopic semi-analytical theory for the description of organic molecules interacting strongly with a cavity mode. Exciton-vibration coupling within the molecule and exciton-cavity interaction are treated on an equal footing by employing a temperature-dependent variational approach. The interplay between strong exciton-vibration coupling and strong exciton-cavity coupling gives rise to a hybrid ground state, which we refer to as the lower polaron polariton. Explicit expressions for the ground-state wave function, the zero-temperature quasiparticle weight of the lower polaron polariton, the photoluminescence line strength, and the mean number of vibrational quanta are obtained in terms of the optimal variational parameters. The dependence of these quantities upon the exciton-cavity coupling strength reveals that strong cavity coupling leads to an enhanced vibrational dressing of the cavity mode, and at the same time a vibrational decoupling of the dark excitons, which in turn results in a lower polaron polariton resembling a single-mode dressed bare lower polariton in the strong-coupling regime. Thermal effects on several observables are briefly discussed.

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Section: B the Generalized Merrifield Transformationmentioning

confidence: 96%

“…(48)-(50) are recovered. Actually, the factor η e −βEη x 2 η e ik(η)n /Z S in I 0−0 and I 0−1 , and the ratios Z x/y /Z S in N…”

mentioning

confidence: 99%

When polarons meet polaritons: Exciton-vibration interactions in organic molecules strongly coupled to confined light fields

Feist

García‐Vidal

2016

Phys. Rev. B

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“…with the same Matsubara decomposition frequency), one can draw a relation to the Matsubara decomposition coefficients given in Eqs. ( 9) and (10), which are attributed to a correlation function between two system-bath coupling contributions. From Eq.…”

Section: B †mentioning

confidence: 99%

“…Such transformation, which is obtained by applying a shift operator 1,4 to compensate the displacement of the equilibrium position in excited-state potentials of vibrational modes compared to the ground-state potential, is known as the polaron transformation (PT). 9 Apart from applications where a quantum mechanical treatment with involvement of vibrational eigenstates was chosen, 10 it has been extensively applied in the context of open quantum systems in the framework of spin-boson models 11 with applications ranging from quantum dots, 12 molecular donor-acceptor complexes, 13 interacting excitonic dimer units 14,15 and light-harvesting complexes 16,17 up to bulk materials, such as organic molecular crystals. [18][19][20][21] In particular, second-order perturbative description of transfer processes in molecular aggregates with separation of reference and interaction Hamiltonian via PT is a widely used application.…”

Section: Introductionmentioning

confidence: 99%

Strong Exciton-Vibrational Coupling in Molecular Assemblies. Dynamics using the Polaron Transformation in HEOM Space

Seibt,

Kühn

2021

Preprint

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In the context of Frenkel exciton dynamics in aggregated molecules the polaron transformation technique facilitates a treatment where diagonal elements attributed to electronic excited-state populations are decoupled from fluctuations associated with vibrational degrees-of-freedom. In this article we describe for the first time how the polaron transformation can be applied in the context of the "Hierarchical Equations of Motion" (HEOM) technique for treatment of open quantum systems with all vibrational components attributed to an environment. By using a generating function approach to introduce a shift in the excited state potential energy surface, we derive hierarchical equations for polaron transformation in analogy to those for time propagation. We demonstrate the applicability of the developed approach by calculating the dynamics of underdamped and overdamped oscillators coupled to electronic excitation of a monomer without and with previous polaron transformation and study the dynamics of the expectation value of the respective vibrational coordinates. Furthermore, we investigate the dynamics of a dimer with a barrier comparable to the thermal energy between the minima of the lower excitonic potential energy surface. It turns out that the assumption of localization at the monomer unit with energetically higher potential minimum, introduced via polaron transformation, has a substantial influence on the transfer dynamics. Here, it makes a clear difference whether the polaron transformation is performed in the local or exciton basis. This reflects the fact that the polaron transformation only accounts for equilibration of the vibrational, but not of the excitonic dynamics. We sketch an approach to compensate this shortcoming in view of obtaining an initial state for the calculation of emission spectra of molecular aggregates.

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“…Such a transformation, which is obtained by applying a shift operator 1,4 to compensate the displacement of the equilibrium position in excited-state potentials of vibrational modes compared to the ground-state potential, is known as the polaron transformation (PT). 9 Apart from applications where a quantum mechanical treatment with involvement of vibrational eigenstates was chosen, 10 it has been extensively applied in the context of open quantum systems in the framework of spinboson models 11 with applications ranging from quantum dots, 12 molecular donor−acceptor complexes, 13 interacting excitonic dimer units, 14,15 and light-harvesting complexes 16,17 up to bulk materials, such as organic molecular crystals. 18−21 In particular, second-order perturbative description of transfer processes in molecular aggregates with separation of reference and interaction Hamiltonian via PT is a widely used application.…”

Section: ■ Introductionmentioning

confidence: 99%

Strong Exciton–Vibrational Coupling in Molecular Assemblies. Dynamics Using the Polaron Transformation in HEOM Space

Seibt

Kühn

2021

J. Phys. Chem. A

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In Frenkel exciton dynamics of aggregated molecules, the polaron transformation (PT) technique leads to decoupling of diagonal elements in the subspace of excited electronic states from vibrations. In this article we describe for the first time how PT becomes applicable in the framework of the “Hierarchical Equations of Motion” (HEOM) approach for treatment of open quantum systems. We extend the concept of formulating operators in HEOM space by deriving hierarchical equations of PT which lead to a shift in the excited state potential energy surface to compensate its displacement. While the assumption of thermal equilibration of the vibrational oscillators, introduced by PT, results in a stationary state in a monomer, in a dimer under the same assumption nonequilibrium dynamics appears because of the interplay of the transfer process and vibrational equilibration. Both vertical transitions generating a vibrationally hot state and initially equilibrated vibrational oscillators evolve toward the same stationary asymptotic state associated with polaron formation. The effect of PT on the dynamics of this process depends on initial excitation and basis representation of the electronic system. The developed approach facilitates a generic formulation of quantum master equations involving perturbative treatment of polaron dynamics.

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Vibronic effects and destruction of exciton coherence in optical spectra of J-aggregates: A variational polaron transformation approach

Cited by 8 publications

References 79 publications

When polarons meet polaritons: Exciton-vibration interactions in organic molecules strongly coupled to confined light fields

When polarons meet polaritons: Exciton-vibration interactions in organic molecules strongly coupled to confined light fields

Strong Exciton-Vibrational Coupling in Molecular Assemblies. Dynamics using the Polaron Transformation in HEOM Space

Strong Exciton–Vibrational Coupling in Molecular Assemblies. Dynamics Using the Polaron Transformation in HEOM Space

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