Accurate and Numerically Efficient r²SCAN Meta-Generalized Gradient Approximation

The Journal of Physical Chemistry Letters, Journal Year: 2020, Volume and Issue: 11(19), P. 8208 - 8215

Published: Sept. 2, 2020

The recently proposed rSCAN functional [ J. Chem. Phys. 2019 150, 161101] is a regularized form of the SCAN Rev. Lett. 2015 115, 036402] that improves SCAN's numerical performance at expense breaking constraints known from exact exchange-correlation functional. We construct new meta-generalized gradient approximation by restoring constraint adherence to rSCAN. resulting maintains rSCAN's while transferable accuracy SCAN.

Language: Английский

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CRYSTAL23: A Program for Computational Solid State Physics and Chemistry

Journal of Chemical Theory and Computation, Journal Year: 2022, Volume and Issue: 19(20), P. 6891 - 6932

Published: Dec. 11, 2022

The Crystal program for quantum-mechanical simulations of materials has been bridging the realm molecular quantum chemistry to solid state physics many years, since its first public version released back in 1988. This peculiarity stems from use atom-centered basis functions within a linear combination atomic orbitals (LCAO) approach and corresponding efficiency evaluation exact Fock exchange series. In particular, this led implementation rich variety hybrid density functional approximations 1998. Nowadays, it is acknowledged by broad community chemists physicists that inclusion fraction exchange-correlation potential theory key better description properties (electronic, magnetic, mechanical, spintronic, lattice-dynamical, etc.). Here, main developments made last five years (i.e., previous release, Crystal17) are presented some their most noteworthy applications reviewed.

Language: Английский

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Relativistic Heavy-Neighbor-Atom Effects on NMR Shifts: Concepts and Trends Across the Periodic Table

Chemical Reviews, Journal Year: 2020, Volume and Issue: 120(15), P. 7065 - 7103

Published: June 23, 2020

Chemical shifts present crucial information about an NMR spectrum. They show the influence of chemical environment on nuclei being probed. Relativistic effects caused by presence atom a heavy element in compound can appreciably, even drastically, alter nearby nuclei. A fundamental understanding such relativistic is important many branches and physical science. This review provides comprehensive overview tools, concepts, periodic trends pertaining to shielding neighboring diamagnetic systems, with particular emphasis "spin-orbit heavy-atom effect light-atom" shift (SO-HALA effect). The analyses tools described this provide guidelines help spectroscopists computational chemists estimate ranges for unknown compound, identify intermediates catalytic other processes, analyze conformational aspects intermolecular interactions, predict series compounds throughout Periodic Table. current snapshot subfield spectroscopy basis framework including future findings field.

Language: Английский

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Benchmarking TD-DFT and Wave Function Methods for Oscillator Strengths and Excited-State Dipole Moments

Journal of Chemical Theory and Computation, Journal Year: 2021, Volume and Issue: 17(2), P. 1117 - 1132

Published: Jan. 25, 2021

Using a set of oscillator strengths and excited-state dipole moments near full configuration interaction quality determined for small compounds, we benchmark the performances several single-reference wave function methods [CC2, CCSD, CC3, CCSDT, ADC(2), ADC(3/2)] time-dependent density-functional theory (TD-DFT) with various functionals (B3LYP, PBE0, M06-2X, CAM-B3LYP, ωB97X-D). We consider impact gauges (length, velocity, mixed) formalisms: equation motion versus linear response, relaxed unrelaxed orbitals, so forth. Beyond expected accuracy improvements neat decrease formalism sensitivity when using higher-order methods, present contribution shows that, both ADC(2) CC2, choice gauge impacts more significantly magnitude than that CCSD yields notable improvement on this transition property as compared to CC2. For moments, switching orbital relaxation appreciably improves CC2 but has rather effect at level. Going from ground excited states, typical errors given method tend roughly triple. Interestingly, ADC(3/2) dipoles are accurate their counterparts, whereas two models do deliver similar absolute energies. Concerning TD-DFT, one finds: (i) negligible all tested (except M06-2X); (ii) deviations ca. 0.10 D ground-state functionals; (iii) strong differences between obtained with, hand, B3LYP PBE0 and, other ωB97X-D, latter group being markedly selected basis set; (iv) better overall performance CAM-B3LYP considered properties. Finally, investigated properties, consistency second-order approaches, not clearly outperform those hinting assessing (or selecting specific functional) results former is systematically well-settled strategy.

Language: Английский

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TURBOMOLE: Today and Tomorrow

Journal of Chemical Theory and Computation, Journal Year: 2023, Volume and Issue: 19(20), P. 6859 - 6890

Published: June 29, 2023

TURBOMOLE is a highly optimized software suite for large-scale quantum-chemical and materials science simulations of molecules, clusters, extended systems, periodic solids. uses Gaussian basis sets has been designed with robust fast applications in mind, ranging from homogeneous heterogeneous catalysis to inorganic organic chemistry various types spectroscopy, light-matter interactions, biochemistry. This Perspective briefly surveys TURBOMOLE's functionality highlights recent developments that have taken place between 2020 2023, comprising new electronic structure methods molecules solids, previously unavailable molecular properties, embedding, dynamics approaches. Select features under development are reviewed illustrate the continuous growth program suite, including nuclear orbital methods, Hartree-Fock-based adiabatic connection models, simplified time-dependent density functional theory, relativistic effects magnetic multiscale modeling optical properties.

Language: Английский

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Replacing hybrid density functional theory: motivation and recent advances

Chemical Society Reviews, Journal Year: 2021, Volume and Issue: 50(15), P. 8470 - 8495

Published: Jan. 1, 2021

New approximations in density functional theory (DFT) offer an opportunity to go beyond hybrids' intrinsic tradeoffs.

Language: Английский

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Machine Learning in QM/MM Molecular Dynamics Simulations of Condensed-Phase Systems

Journal of Chemical Theory and Computation, Journal Year: 2021, Volume and Issue: 17(5), P. 2641 - 2658

Published: April 5, 2021

Quantum mechanics/molecular mechanics (QM/MM) molecular dynamics (MD) simulations have been developed to simulate systems, where an explicit description of changes in the electronic structure is necessary. However, QM/MM MD are computationally expensive compared fully classical as all valence electrons treated explicitly and a self-consistent field (SCF) procedure required. Recently, approaches proposed replace QM with machine learned (ML) models. condensed-phase systems pose challenge for these due long-range interactions. Here, we establish workflow, which incorporates MM environment element type high-dimensional neural network potential (HDNNP). The fitted HDNNP describes potential-energy surface particles electrostatic embedding scheme. Thus, feel force from polarized particles. To achieve chemical accuracy, find that even simple require models strong gradient regularization, large number data points, substantial parameters. address this issue, extend our approach delta-learning scheme, ML model learns difference between reference method (DFT) cheaper semi-empirical (DFTB). We show such scheme reaches accuracy DFT method, while requiring significantly less Furthermore, capable correctly incorporating interactions within cutoff 1.4 nm. It validated by performing retinoic acid water interaction S-adenoslymethioniat cytosine water. presented results indicate promising (QM)ML/MM systems.

Language: Английский

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Organic molecules with inverted gaps between first excited singlet and triplet states and appreciable fluorescence rates

Matter, Journal Year: 2021, Volume and Issue: 4(5), P. 1654 - 1682

Published: March 19, 2021

Language: Английский

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Real-space imaging of anisotropic charge of σ-hole by means of Kelvin probe force microscopy

Science, Journal Year: 2021, Volume and Issue: 374(6569), P. 863 - 867

Published: Nov. 11, 2021

An anisotropic charge distribution on individual atoms, such as σ-holes, may strongly affect the material and structural properties of systems. However, spatial resolution distributions an atom represents a long-standing experimental challenge. In particular, existence σ-hole halogen atoms has been demonstrated only indirectly through determination crystal structures organic molecules containing halogens or with theoretical calculations, consequently calling for its direct visualization. We show that Kelvin probe force microscopy properly functionalized can image quadrupolar carbon monoxide molecule. This opens new way to characterize biological chemical systems in which atomic charges play decisive role.

Language: Английский

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Improving Results by Improving Densities: Density-Corrected Density Functional Theory

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(15), P. 6625 - 6639

Published: April 5, 2022

Density functional theory (DFT) calculations have become widespread in both chemistry and materials, because they usually provide useful accuracy at much lower computational cost than wavefunction-based methods. All practical DFT require an approximation to the unknown exchange-correlation energy, which is then used self-consistently Kohn–Sham scheme produce approximate energy from density. Density-corrected simply study of relative contributions total error. In vast majority calculations, error due density negligible. But with certain classes functionals applied problems, sufficiently large as contribute noticeably, its removal leads better results. These problems include reaction barriers, torsional barriers involving π-conjugation, halogen bonds, radicals anions, most stretched etc. all such cases, use a more accurate significantly improves performance, often simple expedient using Hartree–Fock enough. This Perspective explains what DC-DFT is, where it likely improve results, how can functionals. We also outline challenges prospects for field.

Language: Английский

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