The direct calculation of diabatic states based on configurational uniformity

Nakamura, Hisao; Truhlar, Donald G.

doi:10.1063/1.1412879

Cited by 201 publications

(237 citation statements)

References 124 publications

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“…However, it is preferable over surface hopping methods 63 when a quasi continuum of electronic states is present, as in this case. 64,65 The initial nuclear positions, () (0) derived from exciton-exciton annihilation measurements 70 although larger than other 26 exciton diffusion coefficients of Pc-based amorphous materials. 71 However, the diffusion coefficient of the ZnPc aggregate was estimated by assuming an incoherent regime with an exciton transfer rate of ~1.0 × 10 13 s −1 , which is close to the limit of validity of a first order rate process in a molecular system.…”

Section: Exciton Dynamicsmentioning

confidence: 97%

“…Diabatization approximations are particularly suited for evaluating excitonic couplings between several excited states. [26][27][28][29] Recently, some of us have developed a diabatization scheme to compute excitonic couplings between molecular crystal pairs beyond the two-level approximation. 30 The great advantage of diabatization schemes is that they can deal with the short-range (exchange and overlap) and long-range (Coulombic) contributions of the excitonic couplings on equal footing.…”

Section: Introductionmentioning

confidence: 99%

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Exciton Dynamics in Phthalocyanine Molecular Crystals

2016

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In this paper, the exciton transport properties of an octa(butyl)-substituted metal-free phthalocyanine (H2-OBPc) molecular crystal have been explored by means of a combined computational (molecular dynamics and electronic structure calculations) and theoretical (model Hamiltonian) approximation. The excitonic couplings in phthalocyanines, where multiple quasi-degenerate excited states are present in the isolated chromophore, are computed with a multistate diabatization scheme which is able to capture both short-and long-range excitonic coupling effects. Thermal motions in phthalocyanine molecular crystals at room temperature cause substantial fluctuation of the excitonic couplings between neighboring molecules (dynamic disorder). The average values of the excitonic couplings are found to be not much smaller than the reorganization energy for the excitation energy transfer and the commonly assumed incoherent regime for this class of materials cannot be invoked. A simple but realistic model Hamiltonian is proposed to study the exciton dynamics in phthalocyanine molecular crystals or aggregates beyond the incoherent regime.2

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Section: Exciton Dynamicsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Exciton Dynamics in Phthalocyanine Molecular Crystals

2016

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“…We particularly single out for discussion a new approach called the fourfold way. 43,55,56 The fourfold way allows for the direct calculation of diabatic states and their couplings using the conventional variational and perturbational methods of quantum chemistry. This is particularly important because diabatic representations used for dynamics calculations should not be based on an arbitrary selection of configurations.…”

Section: General Theoretical Considerations and Definitionsmentioning

confidence: 99%

Introductory lecture: Nonadiabatic effects in chemical dynamics

et al. 2004

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Recent progress in the theoretical treatment of electronically nonadiabatic processes is discussed. First we discuss the generalized Born-Oppenheimer approximation, which identifies a subset of strongly coupled states, and the relative advantages and disadvantages of adiabatic and diabatic representations of the coupled surfaces and their interactions are considered. Ab initio diabatic representations that do not require tracking geometric phases or calculating singular nonadiabatic nuclear momentum coupling will be presented as one promising approach for characterizing the coupled electronic states of polyatomic photochemical systems. Such representations can be accomplished by methods based on functionals of the adiabatic electronic density matrix and the identification of reference orbitals for use in an overlap criterion. Next, four approaches to calculating or modeling electronically nonadiabatic dynamics are discussed: (1) accurate quantum mechanical scattering calculations, (2) approximate wave packet methods, (3) surface hopping, and (4) self-consistent-potential semiclassical approaches. The last two of these are particularly useful for polyatomic photochemistry, and recent refinements of these approaches will be discussed. For example, considerable progress has been achieved in making the surface hopping method more applicable to the study of systems with weakly coupled electronic states. This includes introducing uncertainty principle considerations to alleviate the problem of classically forbidden surface hops and the development of an efficient sampling algorithm for low-probability events. A topic whose central importance in a number of quantum mechanical fields is becoming more widely appreciated is the introduction of decoherence into the quantal degrees of freedom to account for the effect of the classical treatment on the other degrees of freedom, and we discuss how the introduction of such decoherence into a self-consistent-potential approximation leads to a reasonably accurate but very practical trajectory method for electronically nonadiabatic processes. Finally, the performances of several dynamical methods for Landau-Zener-type and Rosen-Zener-Demkov-type reactive scattering problems are compared.

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“…8,9 Many other definitions exist. [10][11][12][13][14][15][16] In this paper, we will adopt the second definition given above, appropriate for condensed environments, and we will present three new approaches for generating many-electron states relevant to nonequilibrium processes.…”

Section: Introduction To Diabatic Statesmentioning

confidence: 99%

The initial and final states of electron and energy transfer processes: Diabatization as motivated by system-solvent interactions

Subotnik¹,

Cave²,

Steele³

et al. 2009

The Journal of Chemical Physics

137

192

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For a system which undergoes electron or energy transfer in a polar solvent, we define the diabatic states to be the initial and final states of the system, before and after the nonequilibrium transfer process. We consider two models for the system-solvent interactions: A solvent which is linearly polarized in space and a solvent which responds linearly to the system. From these models, we derive two new schemes for obtaining diabatic states from ab initio calculations of the isolated system in the absence of solvent. These algorithms resemble standard approaches for orbital localization, namely, the Boys and Edmiston-Ruedenberg ͑ER͒ formalisms. We show that Boys localization is appropriate for describing electron transfer ͓Subotnik et al., J. Chem. Phys. 129, 244101 ͑2008͔͒ while ER describes both electron and energy transfer. Neither the Boys nor the ER methods require definitions of donor or acceptor fragments and both are computationally inexpensive. We investigate one chemical example, the case of oligomethylphenyl-3, and we provide attachment/detachment plots whereby the ER diabatic states are seen to have localized electron-hole pairs.

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The direct calculation of diabatic states based on configurational uniformity

Cited by 201 publications

References 124 publications

Exciton Dynamics in Phthalocyanine Molecular Crystals

Exciton Dynamics in Phthalocyanine Molecular Crystals

Introductory lecture: Nonadiabatic effects in chemical dynamics

The initial and final states of electron and energy transfer processes: Diabatization as motivated by system-solvent interactions

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