Assessment of the Performance of Optimally Tuned Range‐Separated Hybrid Functionals for Nuclear Magnetic Shielding Calculations

Prokopiou, Georgia; Autschbach, Jochen; Kronik, Leeor

doi:10.1002/adts.202000083

Cited by 7 publications

(15 citation statements)

References 93 publications

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“…Thus, it seems that the use of uncalibrated exchange-energy densities exacerbates the unphysical contributions from τ MS for t-LMFs, and using a CF provides a better starting point. This holds for the Ne atom and for the σ ∥ p terms of both 1 H and 19 F shieldings in HF. Nevertheless, some artifacts remain, even for the calibrated functionals.…”

Section: Resultsmentioning

confidence: 68%

“…Turning to the "heavy" nuclei in these systems, the clear overestimate of the shieldings for most of the uncalibrated LHs is obvious with τ MS , again increasingly so for the more polar element−hydrogen bonds up to 25 ppm for HF. The problem As done previously, we grouped the shieldings into 1 H, 13 C, and heteronuclei (combining 15 N, 17 O, 19 F, and 31 P). For each subset, we evaluated the standard deviation (SD), the mean signed error (MSE), and the mean absolute error (MAE).…”

Section: Resultsmentioning

confidence: 99%

“…Due to the central importance of NMR spectroscopy in chemistry and related fields, the quantum-chemical calculation of NMR parameters has become a tool of appreciable importance and interest . Methodological improvements in this area in terms of the computational efficiency , , accuracy, − and method validation − are currently being pursued very actively. With the focus of the present work on nuclear shieldings, we note that Kohn–Sham density functional theory (DFT) is the most widely used methodology in view of its good cost–performance ratio.…”

Section: Introductionmentioning

confidence: 99%

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Implementation and Validation of Local Hybrid Functionals with Calibrated Exchange-Energy Densities for Nuclear Shielding Constants

Schattenberg

Kaupp

2021

J. Phys. Chem. A

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A recently reported coupled-perturbed Kohn–Sham implementation to compute nuclear shielding constants with gauge-including atomic orbitals and local hybrid functionals has been extended to cover higher derivatives of the density in the local mixing function (LMF) of the local hybrid as well as the calibration function (CF) needed to deal with the ambiguity of exchange-energy densities. This allowed the first evaluation of state-of-the-art local hybrids with “calibrated” exchange-energy densities for nuclear shieldings. Compared to previously evaluated simpler local hybrids without a CF, appreciable improvements are found for proton shieldings. Furthermore, the recent LH20t functional is still competitive with the outstanding performance of the uncalibrated LH12ct-SsirSVWN and LH12ct-SsifSVWN LHs for heavier nuclei, suggesting that LH20t is possibly the most robust choice of any rung-four functional for computing the nuclear shieldings of main-group nuclei so far. Interestingly, the presence of a CF in the functional significantly reduces the number of artifacts introduced by the widely used Maximoff–Scuseria framework to treat the local kinetic energy τ. The latter occurs in so-called t-LMFs used in many of the present local hybrids. In any case, the use of Dobson’s current-density functional framework is also recommended with more advanced calibrated τ-dependent local hybrid functionals.

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Section: Resultsmentioning

confidence: 68%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Implementation and Validation of Local Hybrid Functionals with Calibrated Exchange-Energy Densities for Nuclear Shielding Constants

Schattenberg

Kaupp

2021

J. Phys. Chem. A

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“…We note in passing the possibility of “optimal tuning” of the range-separation parameter. While this may help improve excitation spectra, its usefulness for nuclear shieldings appears to be limited …”

Section: Resultsmentioning

confidence: 99%

“…This makes a theory-against-theory comparison preferable, provided a benchmark level with sufficiently high accuracy is available. For main-group nuclear shieldings, a number of high-level benchmarks have been put forward, typically based on CCSD(T) “gold standard” data for small molecules. ,,,− However, these data sets usually have been based on a relatively small number of values for a given nucleus, and the different sets often used different basis sets, which may lead to variable accuracy. We therefore decided to construct a larger benchmark set of light main-group nuclear shieldings at a uniform computational level to be used in validation studies of more approximate methods.…”

Section: Introductionmentioning

confidence: 99%

Extended Benchmark Set of Main-Group Nuclear Shielding Constants and NMR Chemical Shifts and Its Use to Evaluate Modern DFT Methods

Schattenberg

Kaupp

2021

J. Chem. Theory Comput.

141

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An extended theoretical benchmark set, NS372, for light main-group nuclear shieldings and NMR shifts has been constructed based on high-level GIAO-CCSD(T)/pcSseg-3//CCSD(T)/cc-pVQZ reference data. After removal of the large static-correlation cases O3, F3 –, and BH from the statistical evaluations for the 17O, 19F, and 11B subsets, the benchmark comprises overall 372 shielding values in 117 molecules with a wide range of electronic-structure situations, containing 124 1H, 14 11B, 93 13C, 43 15N, 31 17O, 47 19F, 14 31P, and 6 33S shielding constants. The CCSD(T)/pcSseg-3 data are shown to be close to the basis-set and method limit and thus provide an excellent benchmark to evaluate more approximate methods, such as density functional approaches. This dataset has been used to evaluate Hartree–Fock (HF) and MP2, and a wide range of exchange–correlation functionals from local density approximation (LDA) to generalized gradient approximations (GGAs) and meta-GGAs (focusing on their current-density functional implementations), as well as global hybrid, range-separated hybrid, local hybrid, and double-hybrid functionals. Starting with absolute shielding constants, the DSD-PBEP86 double hybrid is confirmed to provide the highest accuracy, with an aggregate relative mean absolute error (rel. MAE) of only 0.9%, followed by MP2 (1.1%). MP2 and double hybrids only show larger errors for a few systems with the largest static-correlation effects. The double-hybrid B2GP-PLYP, the two local hybrids cLH12ct-SsirPW92 and cLH12ct-SsifPW92, and the current-density functional meta-GGA cB97M-V follow closely behind (all 1.5%), as do some further functionals, cLH20t and cMN15-L (both 1.6%), as well as B2PLYP and KT3 (both 2.0%). Functionals on the lower rungs of the usual ladder offer the advantage of lower computational cost and access to larger molecules. Closer examination also reveals the best-performing methods for individual nuclei in the test set. Different ways of treating τ-dependent functionals are evaluated. When moving from absolute shielding constants to chemical shifts, some of the methods can benefit from systematic error compensation, and the overall error range somewhat narrows. Further methods now achieve the 2% threshold of relative MAEs, including functionals based on TPSS (TPSSh, cmPSTS).

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Delocalization error: The greatest outstanding challenge in density‐functional theory

Bryenton

Adeleke

Dale

et al. 2022

WIREs Comput Mol Sci

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Every day, density-functional theory (DFT) is routinely applied to computational modeling of molecules and materials with the expectation of high accuracy. However, in certain situations, popular density-functional approximations (DFAs) have the potential to give substantial quantitative, and even qualitative, errors. The most common class of error is delocalization error, which is an overarching term that also encompasses the one-electron self-interaction error.In our opinion, its resolution remains the greatest outstanding challenge in DFT development. In this paper, we review the history of delocalization error and provide several complimentary conceptual pictures for its interpretation, along with illustrative examples of its various manifestations. Approaches to reduce delocalization error are discussed, as is its interplay with other shortcomings of popular DFAs, including treatment of non-bonded repulsion and neglect of London dispersion.

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Assessment of the Performance of Optimally Tuned Range‐Separated Hybrid Functionals for Nuclear Magnetic Shielding Calculations

Abstract: This is the author manuscript accepted for publication and has undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as

Cited by 7 publications

References 93 publications

Implementation and Validation of Local Hybrid Functionals with Calibrated Exchange-Energy Densities for Nuclear Shielding Constants

Implementation and Validation of Local Hybrid Functionals with Calibrated Exchange-Energy Densities for Nuclear Shielding Constants

Extended Benchmark Set of Main-Group Nuclear Shielding Constants and NMR Chemical Shifts and Its Use to Evaluate Modern DFT Methods

Delocalization error: The greatest outstanding challenge in density‐functional theory

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