Simulation of Heme Using DFT + U:  A Step toward Accurate Spin-State Energetics

Scherlis, Damián A.; Cococcioni, Matteo; Sit, Patrick H.‐L.; Marzari, Nicola

doi:10.1021/jp070549l

Cited by 134 publications

(184 citation statements)

References 38 publications

(150 reference statements)

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“…Sophisticated ab initio techniques such as the GW approximation and local correlation methods such as DFT+U , whose traditional realm of application lies in extended systems such as extended oxides and their interfaces, are being increasingly applied to molecular systems and clusters (see for example Refs. 21,[44][45][46][47].…”

Section: Copper Phthalocyanine Dimermentioning

confidence: 99%

Subspace representations inab initiomethods for strongly correlated systems

2011

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We present a generalized definition of subspace occupancy matrices in ab initio methods for strongly correlated materials, such as DFT+U (density functional theory + Hubbard U ) and DFT+DMFT (dynamical mean-field theory), which is appropriate to the case of nonorthogonal projector functions. By enforcing the tensorial consistency of all matrix operations, we are led to a subspace-projection operator for which the occupancy matrix is tensorial and accumulates only contributions which are local to the correlated subspace at hand. For DFT+U , in particular, the resulting contributions to the potential and ionic forces are automatically Hermitian, without resort to symmetrization, and localized to their corresponding correlated subspace. The tensorial invariance of the occupancies, energies, and ionic forces is preserved. We illustrate the effect of this formalism in a DFT+U study using self-consistently determined projectors.

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Section: Copper Phthalocyanine Dimermentioning

confidence: 99%

Subspace representations inab initiomethods for strongly correlated systems

2011

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“…86,87 Difficulties in correctly predicting the relative energies of different spin states are a widely acknowledged shortcoming of DFT calculations. 88,89 Ferric porphyrin chlorides, in particular, have been cited as an illustration of this problem. 65 The ground state is experimentally established as a sextet, [60][61][62][63][64] but the lowest lying sextet and quartet states are predicted to lie close in energy.…”

Section: A Electronic Statementioning

confidence: 99%

Spectroscopic identification of reactive porphyrin motions

Barabanschikov

Demidov

Kubo

et al. 2011

The Journal of Chemical Physics

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Nuclear resonance vibrational spectroscopy (NRVS) reveals the vibrational dynamics of a Mössbauer probe nucleus. Here, 57 Fe NRVS measurements yield the complete spectrum of Fe vibrations in halide complexes of iron porphyrins. Iron porphine serves as a useful symmetric model for the more complex spectrum of asymmetric heme molecules that contribute to numerous essential biological processes. Quantitative comparison with the vibrational density of states (VDOS) predicted for the Fe atom by density functional theory calculations unambiguously identifies the correct sextet ground state in each case. These experimentally authenticated calculations then provide detailed normal mode descriptions for each observed vibration. All Fe-ligand vibrations are clearly identified despite the high symmetry of the Fe environment. Low frequency molecular distortions and acoustic lattice modes also contribute to the experimental signal. Correlation matrices compare vibrations between different molecules and yield a detailed picture of how heme vibrations evolve in response to (a) halide binding and (b) asymmetric placement of porphyrin side chains. The side chains strongly influence the energetics of heme doming motions that control Fe reactivity, which are easily observed in the experimental signal.

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“…The DFT+U was used to predict the electronic structure and magnetic properties of Fe molecules for a range of Coulomb U parameters (U = 2-4 eV), which is reasonable for iron [10,75], and then compared to available data in literature. It was found that GGA+U with U value of 4 eV provided an overall better comparison of the structural, electronic, magnetic properties, and energy level diagram of these systems [76,77].…”

Section: Spin-crossover (Sco)mentioning

confidence: 99%

The DFT+U: Approaches, Accuracy, and Applications

Tolba¹,

Gameel²,

Ali³

et al. 2018

Density Functional Calculations - Recent Progresses of Theory and Application

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This chapter introduces the Hubbard model and its applicability as a corrective tool for accurate modeling of the electronic properties of various classes of systems. The attainment of a correct description of electronic structure is critical for predicting further electronic-related properties, including intermolecular interactions and formation energies. The chapter begins with an introduction to the formulation of density functional theory (DFT) functionals, while addressing the origin of bandgap problem with correlated materials. Then, the corrective approaches proposed to solve the DFT bandgap problem are reviewed, while comparing them in terms of accuracy and computational cost. The Hubbard model will then offer a simple approach to correctly describe the behavior of highly correlated materials, known as the Mott insulators. Based on Hubbard model, DFT+U scheme is built, which is computationally convenient for accurate calculations of electronic structures. Later in this chapter, the computational and semiempirical methods of optimizing the value of the Coulomb interaction potential (U) are discussed, while evaluating the conditions under which it can be most predictive. The chapter focuses on highlighting the use of U to correct the description of the physical properties, by reviewing the results of case studies presented in literature for various classes of materials.

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Simulation of Heme Using DFT + U: A Step toward Accurate Spin-State Energetics

Cited by 134 publications

References 38 publications

Subspace representations inab initiomethods for strongly correlated systems

Subspace representations inab initiomethods for strongly correlated systems

Spectroscopic identification of reactive porphyrin motions

The DFT+U: Approaches, Accuracy, and Applications

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