Density functional theory for doped TiO₂: current research strategies and advancements

Nanotechnology, Journal Year: 2024, Volume and Issue: 35(19), P. 192001 - 192001

Published: Feb. 7, 2024

Abstract Since the inception of density functional theory (DFT) by Hohenberg and Kohn in 1964, it rapidly became an indispensable theoretical tool across various disciplines, such as chemistry, biology, materials science, among others. This has ushered a new era computational research, paving way for substantial advancements fundamental understanding. Today, DFT is routinely employed diverse range applications, probing material properties providing profound understanding mechanisms underlying physical, chemical, biological processes. Even after decades active utilization, improvement principles never been slowed down, meaning that more accurate results are continuously generated with time. work highlights latest achievements acquired specific research field, namely investigations doped TiO 2 systems, which have not comprehensively reviewed summarized yet. Successful progress this niche currently hard to imagine without support DFT. It can accurately reveal introducing desired dopant help find optimal system design application prior proceeding time-consuming expensive experimental research. Hence, evaluating selection most recent studies, we aim highlight pertinent aspects they relate study systems. We also shed light on strengths weaknesses present primary strategies thus far predict systems reliably.

Language: Английский

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Molecular engineering on tyrian puprle natural dye as TiO2 based fined tuned photovoltaic dye material: DFT molecular analysis

Journal of Molecular Graphics and Modelling, Journal Year: 2024, Volume and Issue: 134, P. 108894 - 108894

Published: Oct. 28, 2024

Language: Английский

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Good Practices in Database Generation for Benchmarking Density Functional Theory

Wiley Interdisciplinary Reviews Computational Molecular Science, Journal Year: 2025, Volume and Issue: 15(1)

Published: Jan. 1, 2025

ABSTRACT The hundreds of density functional theory (DFT) methods developed over the past three decades are often referred to as “zoo” DFT approximations. In line with this terminology, numerous benchmark studies might be considered “safari” evaluation efforts, reflecting their abundance, diversity, and wide range application methodological aspects. These benchmarks have played a critical role in establishing dominant approach quantum chemical applications remain essential for selecting an appropriate method specific properties (e.g., reaction energy, barrier height, or noncovalent interaction energy) systems organic, inorganic, organometallic). vital tool both users selection developers design parameterization. This review provides best‐practice guidance on key aspects benchmarking, such quality reference values, dataset size, geometries, basis sets, statistical analysis, electronic availability data. Additionally, we present flowchart assist systematically choosing these aspects, thereby enhancing reliability reproducibility benchmarking studies.

Language: Английский

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Benchmark computations of nearly degenerate singlet and triplet states of N-heterocyclic chromophores. II. Density-based methods

The Journal of Chemical Physics, Journal Year: 2025, Volume and Issue: 162(2)

Published: Jan. 8, 2025

In this paper, we demonstrate the performance of several density-based methods in predicting inversion S1 and T1 states a few N-heterocyclic triangulene based fused ring molecules (popularly known as INVEST molecules) with an eye to identify well performing but cost-effective preliminary screening method. Both conventional linear-response time-dependent density functional theory (LR-TDDFT) ΔSCF (namely maximum overlap method, square-gradient minimization restricted open-shell Kohn–Sham) are considered for excited state computations using exchange–correlation (XC) functionals from different rungs Jacob’s ladder. A well-justified systematism is observed when compared against fully internally contracted multireference configuration interaction singles doubles and/or equation motion coupled-cluster (EOM-CCSD), most important feature being capture spin-polarization presence correlation. set least mean absolute error proposed both approaches, LR-TDDFT ΔSCF, which can be more alternatives on synthesizable larger derivatives templates studied here. We have our findings extensive studies three cyclazine-based molecular templates, additional six related templates. Previous benchmark subsets were conducted domain-based local pair natural orbital-similarity transformed EOM-CCSD (STEOM-CCSD), resulted inadequate evaluation due deficiencies theory. The role exact-exchange, spin-contamination, context DFT comes forefront supports numerical XC these applications. Suitable connections drawn two exciton models, minimal physics governing interactions molecules.

Language: Английский

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Current density functional framework for spin–orbit coupling

The Journal of Chemical Physics, Journal Year: 2022, Volume and Issue: 157(20)

Published: Nov. 7, 2022

Relativistic two-component density functional calculations are carried out in a non-collinear formalism to describe spin-orbit interactions, where the exchange-correlation is constructed as generalization of non-relativistic approximation. Contrary theory (DFT), coupling, however, leads non-vanishing paramagnetic current density. Density functionals depending on kinetic energy density, such meta-generalized gradient approximations, should therefore be framework DFT (CDFT). The latter has previously exclusively been used regime strong magnetic fields. Herein, we present consistent CDFT approach for relativistic DFT, including coupling. Furthermore, assess importance terms ground-state energies, excitation nuclear resonance shielding, and spin-spin coupling constants, well hyperfine Δg-shifts, quadrupole interaction tensor electron (EPR) spectroscopy. most notable changes found EPR properties. impact current-dependent rises with number unpaired electrons, consequently, properties more sensitive toward CDFT. Considerable observed strongly constrained appropriately normed functionals, B97M family TASK. less important when exact exchange incorporated. At same time, kernel ensures stability response all cases. We, therefore, recommend use self-consistent calculations.

Language: Английский

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A Mountaineering Strategy to Excited States: Revising Reference Values with EOM-CC4

Journal of Chemical Theory and Computation, Journal Year: 2022, Volume and Issue: 18(7), P. 4418 - 4427

Published: June 23, 2022

In the framework of computational determination highly accurate vertical excitation energies in small organic compounds, we explore possibilities offered by equation-of-motion formalism relying on approximate fourth-order coupled-cluster (CC) method, CC4. We demonstrate, using an extended set more than 200 reference values based CC including up to quadruples excitations (CCSDTQ), that CC4 is excellent approximation CCSDTQ for excited states with a dominant contribution from single average deviation as 0.003 eV. next assess accuracy several additive basis correction schemes, which obtained compact and high-order method are corrected lower-order calculations performed larger set. Such strategies found be overall very beneficial, though their depends significantly actual scheme. Finally, employed improve theoretical best estimates QUEST database molecules containing between four six (nonhydrogen) atoms, previous were computed at CCSDT level.

Language: Английский

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Visualizing and characterizing excited states from time-dependent density functional theory

Physical Chemistry Chemical Physics, Journal Year: 2023, Volume and Issue: 26(5), P. 3755 - 3794

Published: Dec. 12, 2023

Time-dependent density functional theory (TD-DFT) is the most widely-used electronic structure method for excited states, due to a favorable combination of low cost and semi-quantitative accuracy in many contexts, even if there are well recognized limitations. This Perspective describes various ways which states from TD-DFT calculations can be visualized analyzed, both qualitatively quantitatively. includes not just orbitals densities but also well-defined statistical measures electron-hole separation Frenkel-type exciton delocalization. Emphasis placed on mathematical connections between methods that have often been discussed separately. Particular attention paid charge-transfer diagnostics, provide indicators when may trustworthy its categorical failure describe long-range electron transfer. Measures size charge directly connected underlying transition recommended over more

Language: Английский

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Highly Accurate Prediction of NMR Chemical Shifts from Low-Level Quantum Mechanics Calculations Using Machine Learning

Journal of Chemical Theory and Computation, Journal Year: 2024, Volume and Issue: 20(5), P. 2152 - 2166

Published: Feb. 8, 2024

Theoretical predictions of NMR chemical shifts from first-principles can greatly facilitate experimental interpretation and structure identification molecules in gas, solution, solid-state phases. However, accurate prediction using the gold-standard coupled cluster with singles, doubles, perturbative triple excitations [CCSD(T)] method a complete basis set (CBS) be prohibitively expensive. By contrast, machine learning (ML) methods offer inexpensive alternatives for shift but are hampered by generalization to outside original training set. Here, we propose several new ideas ML H, C, N, O that first introduce novel feature representation, based on atomic shielding tensors within molecular environment an quantum mechanics (QM) method, train it predict shieldings high-level composite theory approaches accuracy CCSD(T)/CBS. In addition, model through progressive active workflow reduces total number expensive calculations required while allowing continuously improve unseen data. Furthermore, algorithm provides error estimation, signaling potential unreliability if is large. Finally, approach keep rotational invariance features tensor vectors (TEVs) yields highest compared similar data augmentation. We illustrate predictive capacity resulting (iShiftML) models across benchmarks, including NS372 set, gas-phase small organic molecules, much larger more complex natural products which accurately differentiate between subtle diastereomers assignments.

Language: Английский

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Orbital-Optimized Versus Time-Dependent Density Functional Calculations of Intramolecular Charge Transfer Excited States

Journal of Chemical Theory and Computation, Journal Year: 2024, Volume and Issue: 20(9), P. 3809 - 3822

Published: May 2, 2024

The performance of time-independent, orbital-optimized calculations excited states is assessed with respect to charge transfer excitations in organic molecules comparison the linear-response time-dependent density functional theory (TD-DFT) approach. A direct optimization method converge on saddle points electronic energy surface used carry out local approximation (LDA) and generalized gradient (GGA) functionals PBE BLYP for a set 27 15 molecules. time-independent approach fully variational provides relaxed state electron from which extent quantified. TD-DFT are generally found provide larger distances compared calculations, even when including orbital relaxation effects Z-vector method. While error excitation relative theoretical best estimates increase up ca. −2 eV TD-DFT, no correlation observed LDA GGA mean absolute ∼0.7 eV, outperforming both global hybrid long-range character. Orbital-optimized B3LYP range-separated CAM-B3LYP selection short- indicate that inclusion exact exchange has small effect distance, while it significantly improves energy, best-performing providing an typically around 0.15 eV.

Language: Английский

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Minimal Auxiliary Basis Set Approach for the Electronic Excitation Spectra of Organic Molecules

The Journal of Physical Chemistry Letters, Journal Year: 2023, Volume and Issue: 14(7), P. 1968 - 1976

Published: Feb. 14, 2023

We report a minimal auxiliary basis model for time-dependent density functional theory (TDDFT) with hybrid functionals that can accurately reproduce excitation energies and absorption spectra from TDDFT while reducing cost by about 2 orders of magnitude. Our method, dubbed TDDFT-ris, employs the resolution-of-the-identity technique just one s-type function per atom linear response operator, where Gaussian exponents are parametrized across periodic table using tabulated atomic radii single global scaling factor. By tuning on small test set, we determine functional-independent scale factor balances errors in spectra. Benchmarked organic molecules compared to standard TDDFT, TDDFT-ris has an average energy error only 0.06 eV yields close agreement TDDFT. Thus, enables simulation realistic large would be inaccessible

Language: Английский

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