Quantum dynamical simulation of intramolecular singlet fission in covalently coupled pentacene dimers

Reddy, S. Rajagopala; Coto, Pedro B.; Thoss, Michael

doi:10.1063/1.5109897

Cited by 22 publications

(9 citation statements)

References 112 publications

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“…Due to the proposition of the promising application to organic solar cells, , more and more findings and knowledge on SF have been accumulated so far, which contribute to unravelling the mechanism and underlined electronic structures − as well as to designing and synthesizing novel SF molecules. − Theoretical molecular design of the SF system can be organized step by step as follows for instance. The energy level matching condition is required for SF to be exothermic or, at least, isothermic [ E (S 1 ) – 2 E (T 1 ) > 0 or ≈0], , which is refined by the diradical character-based design providing more chemically intuitive point of view into diradicaloid SF molecules. , Subsequently, the inter-/intra-chromophore packing is necessary to be examined since the electronic coupling between chromophores, which is sensitive to packing configuration, is a key factor for the SF rate and TT yield. ,, The exciton relaxation dynamics for SF is finally assessed by considering vibronic coupling in addition to the above energy level matching and electronic couplings. − …”

Section: Introductionmentioning

confidence: 99%

Stabilization of Charge-Transfer States in Pentacene Crystals and Its Role in Singlet Fission

et al. 2021

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We theoretically investigate the role of charge-transfer (CT) states being stabilized by surrounding environments on singlet fission (SF) dynamics in a pentacene crystal. Using a polarizable force field to calculate induction energy by the surrounding molecules, the stabilization of the CT dimer energy is assessed for its convergence in massively large crystalline cells. The behavior of the convergence and the converged energies are found to depend on the local dimer configuration, that is, parallel slip-stack or tilted face-to-edge packings. Using the resultant crystalline-effective CT energies, the SF dynamics simulation based on the quantum master equation is performed for both dimers and multimers in the crystal. It is found for the multimer that the populations of the Frenkel excitons and CT excitons exhibit recurrence motions between neighboring sites and that double-triplet excitons are then gradually generated in an ultrafast timescale (<100 fs). From the analysis on relative relaxation factors (RRFs) between the adiabatic exciton states, the mechanism of the rapid SF rate in the crystal is revealed, where the intrusions of the diabatic CT configurations into all the adiabatic states effectively accelerate the SF process. Furthermore, the RRF is used to predict the double-triplet exciton yield at the extreme of the extended large size cell. The present findings will provide a clue to construct design guidelines for efficient SF based on the control of CT energy by environmental engineering.

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Section: Introductionmentioning

confidence: 99%

Stabilization of Charge-Transfer States in Pentacene Crystals and Its Role in Singlet Fission

et al. 2021

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“…Finally, we comment briefly on why two other common tensor network methods appear unsuitable for a full quantum dynamics simulation of the current problem (for a more detailed comparison see 52 ). We do not discuss MCTDH here, since it was extensively explained in previous works 11,23,24,[29][30][31] .…”

Section: Relation To Other Tensor Network Techniquesmentioning

confidence: 99%

“…To accomplish a faithful simulation of the quantum dynamics following the light excitation, a variety of methods has been applied, including multi-configurational time-dependent Hartree (MCTDH) [23][24][25] , Redfield theory 26,27 and time-dependent wave packet diffusion (TDWPD) 28 . However, despite numerous investigations, there has been few numerically unbiased simulations of a full microscopic Hamiltonian that is generated from first principles for both, electronic molecular and vibronic degrees of freedom 12,29 . Additionally, most time-evolution schemes used so far are either valid only in the weak-coupling regime (Redfield theory) or require an ad-hoc decomposition of the vibrational degrees of freedoms into clusters 11,12 (multilayer-MCTDH 30,31 ).…”

Section: Introductionmentioning

confidence: 99%

Quantum dynamics simulation of intramolecular singlet fission in covalently linked tetracene dimer

Mardazad,

Xu,

Yang

et al. 2021

Preprint

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In this work we study singlet fission in tetracene para-dimers, covalently linked by a phenyl group. In contrast to most previous works, we account for the full quantum dynamics of the combined excitonic and vibrational system. For our simulations we choose a numerically unbiased representation of the molecule's wave function enabling us to compare with experiments, exhibiting good agreement. Having access to the full wave function allows us to study in detail the post-quench dynamics of the excitons. Here, one of our main findings is the identification of a time scale t 0 ≈ 35 fs dominated by coherent dynamics.It is within this time scale that the larger fraction of the singlet fission yield is generated.We also report on a reduced number of phononic modes that play a crucial role for the energy transfer between excitonic and vibrational system. Notably, the oscillation frequency of these modes coincides with the observed electronic coherence time t 0 . We extend our investigations by also studying the dependency of the dynamics on the excitonic energy levels that, for instance, can be experimentally tuned by means of the solvent polarity.Here, our findings indicate that the singlet fission yield can be doubled while the electronic coherence time t 0 is mainly unaffected.

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“…Although the GBOA is possibly the most practical strategy to deal with chemical problems in which only a handful of electronic states play a significant role, the calculation of NACs and quasi-diabatic states becomes a formidable task for situations involving a large number of energetically close-lying PES, for example when metal centers 21,22 and highly excited electronic states are involved 23,24 . These situations arise as well in energy and charge transfer scenarios, where the electronic and nuclear dynamics become inextricable and which are often approached via model Hamiltonians [25][26][27][28][29] . Nonetheless, GBOA non-adiabatic dynamics, both fully quantummechanical and mixed quantum-classical, and involving a large number of electronic states, are still feasible under certain approximations 19,24,30 and there is much interest in the further development of approaches to obtain NACs in dense electronic manifolds 31,32 .…”

Section: Introductionmentioning

confidence: 99%

Non-adiabatic quantum dynamics without potential energy surfaces based on second-quantized electrons: application within the framework of the MCTDH method

Sasmal,

Vendrell

2020

Preprint

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A first principles quantum formalism to describe the non-adiabatic dynamics of electrons and nuclei based on a second quantization representation (SQR) of the electronic motion combined with the usual representation of the nuclear coordinates is introduced. This procedure circumvents the introduction of potential energy surfaces and non-adiabatic couplings, providing an alternative to the Born-Oppenheimer approximation. An important feature of the molecular Hamiltonian in the mixed first quantized representation for the nuclei and the SQR representation for the electrons is that all degrees of freedom, nuclear positions and electronic occupations, are distinguishable. This makes the approach compatible with various tensor decomposition ansätze for the propagation of the nuclear-electronic wavefunction. Here, we describe the application of this formalism within the multi-configuration time-dependent Hartree (MCTDH) framework and its multilayer generalization, corresponding to Tucker and hierarchical Tucker tensor decompositions of the wavefunction, respectively. The approach is applied to the calculation of the photodissociation cross-section of the HeH + molecule under extreme ultraviolet irradiation, which features non-adiabatic effects and quantum interferences between the two possible fragmentation channels, He+H + and He + +H. These calculations are compared with the usual description based on ab initio potential energy surfaces and non-adiabatic coupling matrix elements, which fully agree. The proof-of-principle calculations serve to illustrate the advantages and drawbacks of this formalism, which are discussed in detail, as well as possible ways to overcome them. We close with an outlook of possible application domains where the formalism might outperform the usual approach, for example in situations that combine a strong static correlation of the electrons with non-adiabatic electronic-nuclear effects.

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Quantum dynamical simulation of intramolecular singlet fission in covalently coupled pentacene dimers

Cited by 22 publications

References 112 publications

Stabilization of Charge-Transfer States in Pentacene Crystals and Its Role in Singlet Fission

Stabilization of Charge-Transfer States in Pentacene Crystals and Its Role in Singlet Fission

Quantum dynamics simulation of intramolecular singlet fission in covalently linked tetracene dimer

Non-adiabatic quantum dynamics without potential energy surfaces based on second-quantized electrons: application within the framework of the MCTDH method

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