Density matrix renormalization group for <i>ab initio</i> Calculations and associated dynamic correlation methods: A review of theory and applications

Yanai, Takeshi; Kurashige, Yuki; Mizukami, Wataru; Chalupský, Jakub; Lan, Tran Nguyen; Saitow, Masaaki

doi:10.1002/qua.24808

Cited by 173 publications

(192 citation statements)

References 318 publications

(504 reference statements)

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“…[9,[13][14][15][16][17][18][19] However, albeit DFT is in principle capable of treating open-shell molecules with multi-reference character, [20] it is known that the currently available density functional approximations often perform poorly in such cases. [12,21] It is therefore preferable to employ from the outset multireference approaches such as the Complete-Active-Space Self-Consistent-Field (CASSCF) method and the Density Matrix Renormalization Group (DMRG) algorithm [22][23][24][25][26][27][28][29][30][31] in order to obtain a qualitatively correct zeroth-order wave function for these systems.…”

Section: Introductionmentioning

confidence: 99%

On the multi-reference nature of plutonium oxides: PuO₂²⁺, PuO₂, PuO₃ and PuO₂(OH)₂

Boguslawski

Réal

Tecmer

et al. 2017

Phys. Chem. Chem. Phys.

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Actinide-containing complexes present formidable challenges for electronic structure methods due to the large number of degenerate or quasi-degenerate electronic states arising from partially occupied 5f and 6d shells. Conventional multi-reference methods can treat active spaces that are often at the upper limit of what is required for a proper treatment of species with complex electronic structures, leaving no room for verifying their suitability. In this work we address the issue of properly defining the active spaces in such calculations, and introduce a protocol to determine optimal active spaces based on the use of the Density Matrix Renormalization Group algorithm and concepts of quantum information theory. We apply the protocol to elucidate the electronic structure and bonding mechanism of volatile plutonium oxides (PuO 3 and PuO 2 (OH) 2 ), species associated with nuclear safety issues for which little is known about the electronic structure and energetics. We show how, within a scalar relativistic framework, orbital-pair correlations can be used to guide the definition of optimal active spaces which provide an accurate description of static/non-dynamic electron correlation, as well as to analyse the chemical bonding beyond a simple orbital model. From this bonding analysis we are able to show that the addition of oxo-or hydroxo-groups to the plutonium dioxide species considerably changes the pi-bonding mechanism with respect to the bare triatomics, resulting in bent structures with considerable multi-reference character.

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Section: Introductionmentioning

confidence: 99%

On the multi-reference nature of plutonium oxides: PuO₂²⁺, PuO₂, PuO₃ and PuO₂(OH)₂

Boguslawski

Réal

Tecmer

et al. 2017

Phys. Chem. Chem. Phys.

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“…21 Similar limitations apply to restricted active space state interaction (RASSI)-based calculations of HFCs. 22 Recent density matrix renormalization group (DMRG) calculations of hyperfine couplings 23 have so far also been limited to small molecules, and to scalar relativistic levels. 24 Coupled-cluster and configuration-interaction calculations of g-tensors [25][26] and relativistic coupled-cluster calculations of HFC tensors 27 suffer from the same limitations.…”

Section: Introductionmentioning

confidence: 99%

Four-Component Relativistic Density Functional Theory Calculations of EPRg- and Hyperfine-Coupling Tensors Using Hybrid Functionals: Validation on Transition-Metal Complexes with Large Tensor Anisotropies and Higher-Order Spin–Orbit Effects

et al. 2015

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The four-component matrix Dirac-Kohn-Sham (mDKS) implementation of EPR g-and hyperfine A-tensor calculations within a restricted kinetic balance framework in the ReSpect code has been extended to hybrid functionals. The methodology is validated for an extended set of small 4d 1 and 5d 1 [MEXn] q systems, and for a series of larger Ir(II) and Pt(III) d 7 complexes (S=1/2) with particularly large g-tensor anisotropies. Different density functionals (PBE, BP86, B3LYP-xHF, PBE0-xHF) with variable exact-exchange admixture x (ranging from 0% to 50%) have been evaluated, and the influence of structure and basis set has been examined. Notably, hybrid functionals with exact-exchange admixture of about 40% provide the best agreement with experiment and clearly outperform the generalized-gradient approximation (GGA) functionals, in particular for the hyperfine couplings. Comparison with computations at the one-component second-order perturbational level within the DouglasKroll-Hess framework (1c-DKH), and a scaling of the speed of light at the four-component mDKS level, provide insight into the importance of higher-order relativistic effects for both properties. In the more extreme cases of some iridium(II) and platinum(III) complexes, the widely used leading-order perturbational treatment of SO effects in EPR calculations fails to reproduce not only the magnitude but also the sign of certain g-shift components (with the contribution of higher-order SO effects amounting to several hundreds of ppt in 5d complexes). The four-component hybrid mDKS calculations perform very well, giving overall good agreement with the experimental data.

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“…Therefore a number of approximate schemes have been introduced in recent years where the complexity and amount of required information about the active space are reduced. 34 For example, canonical transformation (CT) theory which was introduced by Chan and Yanai discards all density matrices of higher than second order. [35][36][37][38] In Zgid and Chan's cumulant version of SC-NEVPT2 and Yanai's cumulant versions of DMRG-CASPT2 and DMRG-MRCI higher order density matrices are approximated by lower rank cumulant expansions.…”

Section: Introductionmentioning

confidence: 99%

A projected approximation to strongly contracted N-electron valence perturbation theory for DMRG wavefunctions

Roemelt

Guo

Chan

2016

The Journal of Chemical Physics

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A novel approach to strongly contracted N-electron valence perturbation theory (SC-NEVPT2) as a means of describing dynamic electron correlation for quantum chemical density matrix renormalization group (DMRG) calculations is presented. In this approach the strongly contracted perturber functions are projected onto a renormalized Hilbert space. Compared to a straightforward implementation of SC-NEVPT2 with DMRG wavefunctions, the computational scaling and storage requirements are reduced. This favorable scaling opens up the possibility of calculations with larger active spaces. A specially designed renormalization scheme ensures that both the electronic ground state and the perturber functions are well represented in the renormalized Hilbert space.

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Density matrix renormalization group for ab initio Calculations and associated dynamic correlation methods: A review of theory and applications

Cited by 173 publications

References 318 publications

On the multi-reference nature of plutonium oxides: PuO₂²⁺, PuO₂, PuO₃ and PuO₂(OH)₂

On the multi-reference nature of plutonium oxides: PuO₂²⁺, PuO₂, PuO₃ and PuO₂(OH)₂

Four-Component Relativistic Density Functional Theory Calculations of EPRg- and Hyperfine-Coupling Tensors Using Hybrid Functionals: Validation on Transition-Metal Complexes with Large Tensor Anisotropies and Higher-Order Spin–Orbit Effects

A projected approximation to strongly contracted N-electron valence perturbation theory for DMRG wavefunctions

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Density matrix renormalization group for ab initio Calculations and associated dynamic correlation methods: A review of theory and applications

Cited by 173 publications

References 318 publications

On the multi-reference nature of plutonium oxides: PuO22+, PuO2, PuO3 and PuO2(OH)2

On the multi-reference nature of plutonium oxides: PuO22+, PuO2, PuO3 and PuO2(OH)2

Four-Component Relativistic Density Functional Theory Calculations of EPRg- and Hyperfine-Coupling Tensors Using Hybrid Functionals: Validation on Transition-Metal Complexes with Large Tensor Anisotropies and Higher-Order Spin–Orbit Effects

A projected approximation to strongly contracted N-electron valence perturbation theory for DMRG wavefunctions

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On the multi-reference nature of plutonium oxides: PuO₂²⁺, PuO₂, PuO₃ and PuO₂(OH)₂

On the multi-reference nature of plutonium oxides: PuO₂²⁺, PuO₂, PuO₃ and PuO₂(OH)₂