Spin densities from subsystem density-functional theory: Assessment and application to a photosynthetic reaction center complex model

Solovyeva, Alisa; Pavanello, Michele; Neugebauer, Johannes

doi:10.1063/1.4709771

Cited by 38 publications

(85 citation statements)

References 74 publications

(66 reference statements)

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“…But even if a supermolecular basis set is used, charge-and spin-localized states may still be converged because of the repulsive components in the embedding potential when using standard approximations for the non-additive kinetic-energy contribution. 40 In summary, we can use FDE to converge the electronic structure to specific charge-localized states, which can be regarded as (quasi-)diabatic states. A similar strategy has been used by the Warshel group 55, 56 to converge a SCF to diabatic states reflecting certain valence bond structures, so that empirical valence bond model Hamiltonians can be parametrized.…”

Section: B Fde For Electron Transfer: Fde-etmentioning

confidence: 99%

“…[27][28][29][30][31][32][33] An alternative to TDDFT is the constrained variational DFT (CV(4)-DFT) theory, which does not suffer from the failure in the prediction of long-range CT excitations. 34 Subsystem DFT [35][36][37] and the related frozen-density embedding (FDE) method 38 can effectively produce chargeand spin-localized states, 39,40 which naturally can be considered as diabatic states. 41 For the special case of charge-migration processes, we have shown that subsystem density-functional theory 35,36 can be applied to calculate both diagonal and off-diagonal elements of the Hamiltonian H from Eq.…”

Section: Introductionmentioning

confidence: 99%

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Describing long-range charge-separation processes with subsystem density-functional theory

Solovyeva

Pavanello

Neugebauer

2014

The Journal of Chemical Physics

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Long-range charge-transfer processes in extended systems are difficult to describe with quantum chemical methods. In particular, cost-effective (non-hybrid) approximations within time-dependent density functional theory (DFT) are not applicable unless special precautions are taken. Here, we show that the efficient subsystem DFT can be employed as a constrained DFT variant to describe the energetics of long-range charge-separation processes. A formal analysis of the energy components in subsystem DFT for such excitation energies is presented, which demonstrates that both the distance dependence and the long-range limit are correctly described. In addition, electronic couplings for these processes as needed for rate constants in Marcus theory can be obtained from this method. It is shown that the electronic structure of charge-separated states constructed by a positively charged subsystem interacting with a negatively charged one is difficult to converge - charge leaking from the negative subsystem to the positive one can occur. This problem is related to the delocalization error in DFT and can be overcome with asymptotically correct exchange-correlation (XC) potentials or XC potentials including a sufficiently large amount of exact exchange. We also outline an approximate way to obtain charge-transfer couplings between locally excited and charge-separated states.

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Section: B Fde For Electron Transfer: Fde-etmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Describing long-range charge-separation processes with subsystem density-functional theory

Solovyeva

Pavanello

Neugebauer

2014

The Journal of Chemical Physics

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“…58,59 It has been shown 35,36,58 that FDE generates charge-localized states if one subsystem density is constrained to integrate to a number of electrons different from what would yield charge neutrality.…”

Section: Frozen Density Embedding Formulation Of Subsystem Dftmentioning

confidence: 99%

Quantifying Environmental Effects on the Decay of Hole Transfer Couplings in Biosystems

Ramos

Pavanello

2014

J. Chem. Theory Comput.

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In the past two decades, many research groups worldwide have tried to understand and categorize simple regimes in the charge transfer of such biological systems as DNA. Theoretically speaking, the lack of exact theories for electron-nuclear dynamics on one side, and poor quality of the parameters needed by model Hamiltonians and nonadiabatic dynamics alike (such as couplings and site energies) on the other, are the two main difficulties for an appropriate description of the charge transfer phenomena. In this work, we present an application of a previously benchmarked and linear-scaling subsystem DFT method for the calculation of couplings, site energies and superexchange decay factors (β ) of several biological donor-acceptor dyads, as well as double stranded DNA oligomers comprised of up to 5 base pairs. The calculations are all-electron, and provide a clear view of the role of the environment on superexchange couplings in DNA -they follow experimental trends and confirm previous semiempirical calculations. The subsystem DFT method is proven to be an excellent tool for long-range, bridge-mediated coupling and site energy calculations of embedded molecular systems.

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“…In this role, they are shown to be successful provided that there is weak overlap between electron densities of the subsystems. Weakly interacting subsystems, such as hydrogen-bonded systems [30][31][32][33][34][35], van der Waals complexes [30,[36][37][38], ionic bonds, and even charge transfer systems [16,17,39] are shown to be successfully reproduced by FDE.…”

Section: Introductionmentioning

confidence: 99%

Periodic subsystem density-functional theory

Genova¹,

Ceresoli²,

Pavanello³

2014

The Journal of Chemical Physics

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By partitioning the electron density into subsystem contributions, the Frozen Density Embedding (FDE) formulation of subsystem Density Functional Theory (DFT) has recently emerged as a powerful tool for reducing the computational scaling of Kohn-Sham DFT. To date, however, FDE has been employed to molecular systems only. Periodic systems, such as metals, semiconductors, and other crystalline solids have been outside the applicability of FDE, mostly because of the lack of a periodic FDE implementation. To fill this gap, in this work we aim at extending FDE to treat subsystems of molecular and periodic character. This goal is achieved by a dual approach. On one side, the development of a theoretical framework for periodic subsystem DFT. On the other, the realization of the method into a parallel computer code. We find that periodic FDE is capable of reproducing total electron densities and (to a lesser extent) also interaction energies of molecular systems weakly interacting with metallic surfaces. In the pilot calculations considered, we find that FDE fails in those cases where there is appreciable density overlap between the subsystems. Conversely, we find FDE to be in semiquantitative agreement with Kohn-Sham DFT when the inter-subsystem density overlap is low. We also conclude that to make FDE a suitable method for describing molecular adsorption at surfaces, kinetic energy density functionals that go beyond the GGA level must be employed.

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Spin densities from subsystem density-functional theory: Assessment and application to a photosynthetic reaction center complex model

Cited by 38 publications

References 74 publications

Describing long-range charge-separation processes with subsystem density-functional theory

Describing long-range charge-separation processes with subsystem density-functional theory

Quantifying Environmental Effects on the Decay of Hole Transfer Couplings in Biosystems

Periodic subsystem density-functional theory

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