Exploring the Light-Capturing Properties of Photosynthetic Chlorophyll Clusters Using Large-Scale Correlated Calculations

Suomivuori, Carl‐Mikael; Winter, N.; Hättig, Christof; Sundholm, Dage; Kaila, Ville R. I.

doi:10.1021/acs.jctc.6b00237

Cited by 36 publications

(66 citation statements)

References 76 publications

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“…Recently, Suomivuori et al published a computational study on the lowest vertical excitation energies of a model system of the special chlorophyll/bacteriochlorophyll pigment center P700 of photosystem I, where the label P700 refers to the absorption peak at 700 nm. The P700 tetramer model is shown in Figure .…”

Section: Resultsmentioning

confidence: 99%

“…It consists of four chlorine molecules ligated with histidine residues and water. In their study Suomivuori et al used the algebraic diagrammatic construction through second‐order ADC(2) approach, providing highly accurate ab‐initio data for a multimeric compound. The P700 tetramer model consists of 198 atoms and serves in this work as a test system for assessing the accuracy of the different approximative methods applied in our work.…”

Section: Resultsmentioning

confidence: 99%

“…As an example application for a larger system, we have calculated the five lowest singlet vertical excitation energies of a tetrameric P700 model, taken from Ref. . The model system is depicted in Figure .…”

Section: Computational Detailsmentioning

confidence: 99%

“…Instead we use the new methodology to investigate the impact of the RI and ADMM approximations on the accuracy of linear and quadratic response properties. As examples we consider vertical excitation energies, static polarizabilities, and static hyperpolarizabilities for a small benchmark consisting of 11 molecules, and vertical excitation energies for a tetramer P700 model system consisting of 198 atoms. We commence in Section 2 by introducing the theoretical framework for the response calculations.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Accelerating Kohn‐Sham response theory using density fitting and the auxiliary‐density‐matrix method

Kumar

Fliegl

Jensen

et al. 2018

Int J of Quantum Chemistry

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An extension of the formulation of the atomic-orbital-based response theory of Larsen et al., JCP 113, 8909 (2000) is presented. This new framework has been implemented in LSDalton and allows for the use of Kohn-Sham density-functional theory with approximate treatment of the Coulomb and Exchange contributions to the response equations via the popular resolution-of-the-identity approximation as well as the auxiliary-density matrix method (ADMM). We present benchmark calculations of ground-state energies as well as the linear and quadratic response properties: vertical excitation energies, polarizabilities, and hyperpolarizabilities. The quality of these approximations in a range of basis sets is assessed against reference calculations in a large aug-pcseg-4 basis. Our results confirm that density fitting of the Coulomb contribution can be used without hesitation for all the studied properties. The ADMM treatment of exchange is shown to yield high accuracy for ground-state and excitation energies, whereas for polarizabilities and hyperpolarizabilities the performance gain comes at a cost of accuracy. Excitation energies of a tetrameric model consisting of units of the P700 special pigment of photosystem I have been studied to demonstrate the applicability of the code for a large system. K E Y W O R D S ADMM, density fitting, Kohn-Sham DFT response theory, RI | I N TR ODU C TI ONIn molecular electronic-structure theory, an essential step is the evaluation of two-electron integrals over one-electron basis functions. The explicit evaluation of these integrals comes at a high computational cost, and from the dawn of quantum chemistry, approximations have been introduced both to speed up molecular calculations and to reduce memory requirements. [1] Such approximate methods have been widely developed for the calculation of energies and gradients, but less attention has been given to developing these methods for the calculation of molecular properties.The most widely used approach to approximate the Coulomb and exchange integrals is density fitting, also known as the resolution-of-theidentity (RI) approximation. In this approximation products of two one-electron basis functions are expanded in one-center auxiliary functions, and thus, the evaluation of four-center two-electron integrals is replaced by the evaluation of two-and three-center two-electron integrals and the solution of a set of linear equations. RI significantly improves performance with a limited impact on the accuracy and has therefore been applied to Hartree-Fock (HF)/Kohn-Sham (KS) theory, as well as correlated methods. [22][23][24][25][26][27] An important alternative approach is the Cholesky-decomposition (CD) technique [28][29][30][31][32] which to a large extent can be thought of as a special kind of density fitting where the auxiliary basis functions are obtained from the set of products between two one-electron basis functions through Cholesky-decomposition.Combined with J-engine techniques [33][34][35] RI gives tremendous speed-ups [8,9] for C...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Computational Detailsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Accelerating Kohn‐Sham response theory using density fitting and the auxiliary‐density‐matrix method

Kumar

Fliegl

Jensen

et al. 2018

Int J of Quantum Chemistry

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“…A local CC2 approach using the Laplace transformation was used to compute an EE of the pyrene–phenothiazine–isoalloxazine triad with more than 1,300 basis functions taking a week on six CPUs . A Laplace transformed variant of scaled opposite spin ADC(2), which also makes use of the reduced virtual approach made it possible to compute EEs of photosynthetic chlorophyll clusters which may be as big as 200 atoms . A more proper treatment of the virtual space is achieved in the PNO–CC2 implementation of Helmich and Hättig .…”

Section: Benchmarksmentioning

confidence: 99%

Single‐reference coupled cluster methods for computing excitation energies in large molecules: The efficiency and accuracy of approximations

Izsák

2019

WIREs Comput Mol Sci

100

110

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While methodological developments in the last decade made it possible to compute coupled cluster (CC) energies including excitations up to a perturbative triples correction for molecules containing several hundred atoms, a similar breakthrough has not yet been reported for excited state computations. Accurate CC methods for excited states are still expensive, although some promising candidates for an efficient and accurate excited state CC method have emerged recently. This review examines the various approximation schemes with particular emphasis on their performance for excitation energies and summarizes the best state-of-the-art results which may pave the way for a robust excited state method applicable to molecules of hundreds of atoms.Among these, special attention will be given to exploiting the techniques of similarity transformation, perturbative approximations as well as integral decomposition, local and embedding techniques within the equation of motion CC framework. This article is categorized under: Electronic Structure Theory > Ab Initio Electronic Structure Methods Structure and Mechanism > Molecular Structures K E Y W O R D S accuracy, coupled cluster, efficiency, excited states, single reference | INTRODUCTIONIn their lucid review written a few years ago, 1 Sneskov and Christiansen discussed the various coupled cluster (CC) methods available for excited states. Using the systematic machinery of response theory, they described a hierarchy of methods, established a link between response theory and equation of motion (EOM) methods, and finished by discussing a number of approaches that might be used to reduce the computational cost. The present review aims at providing an overview of efficient methods available primarily for large molecules, and hence the emphasis will be laid more upon recent methodological advances which reduce the cost and on the extent this affects the accuracy of these methods. For ground state calculations, choosing a reference method for benchmarks is quite easy, since the CC singles doubles and perturbative triples, or CCSD(T), ansatz 2 is not only widely regarded as the gold standard of quantum chemistry, but it has also recently become possible to compute CCSD(T) energies for molecules containing several hundred atoms. 3 For excited states, progress has been

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Natural and Artificial Photosynthesis

Pantazis¹

2021

Solar‐to‐Chemical Conversion

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Exploring the Light-Capturing Properties of Photosynthetic Chlorophyll Clusters Using Large-Scale Correlated Calculations

Cited by 36 publications

References 76 publications

Accelerating Kohn‐Sham response theory using density fitting and the auxiliary‐density‐matrix method

Accelerating Kohn‐Sham response theory using density fitting and the auxiliary‐density‐matrix method

Single‐reference coupled cluster methods for computing excitation energies in large molecules: The efficiency and accuracy of approximations

Natural and Artificial Photosynthesis

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