A comparative assessment of density functional approximations for inner reorganization energy: insights from small molecules models with varying degrees of charge delocalization

Theoretical Chemistry Accounts, Journal Year: 2025, Volume and Issue: 144(6)

Published: May 16, 2025

Language: Английский

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Nonlinear optical properties of natural hydroxyanthraquinones studied using density functional theory (DFT) technique

Journal of Photochemistry and Photobiology A Chemistry, Journal Year: 2023, Volume and Issue: 446, P. 115151 - 115151

Published: Sept. 2, 2023

Language: Английский

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Use of FLOSIC for understanding anion-solvent interactions

The Journal of Chemical Physics, Journal Year: 2023, Volume and Issue: 159(15)

Published: Oct. 20, 2023

An Achille's heel of lower-rung density-functional approximations is that the highest-occupied-molecular-orbital energy levels anions, known to be stable or metastable in nature, are often found positive worst case above lowest-unoccupied-molecular-orbital on neighboring complexes not expected accept charge. A trianionic example, [Cr(C2O4)3]3-, interest for constraining models linking Cr isotope ratios rock samples oxygen Earth's atmosphere over geological timescales. Here we describe how crowd sourcing can used carry out self-consistent Fermi-Löwdin-Orbital-Self-Interaction corrected calculations (FLOSIC) this trianion solution. The give a physically correct description electronic structure and water. In contrast, uncorrected local density approximation (LDA) result approximately half anion charge being transferred water bath due effects self-interaction error. Use group-theory intrinsic sparsity theory enables roughly 125 times faster than our initial implementation large N limit reached here. By integrating densities Coulomb potentials regions space analyzing core-level shifts O atoms as function position functional, unambiguously show FLOSIC, relative LDA, reverses incorrect solute-solvent transfer trianion-water complex. comparison other functionals investigated herein, including Hartree-Fock approximation, FLOSIC 1s eigenvalues provide best agreement with experimental core ionization energies.

Language: Английский

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Local Second Order Mo̷ller-Plesset Theory with a Single Threshold Using Orthogonal Virtual Orbitals: A Distributed Memory Implementation

Journal of Chemical Theory and Computation, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 2, 2024

In order to alleviate the computational burden associated with superlinear compute scalings molecular size in electron correlation methods, researchers have developed local methods that wisely treat relatively small contributions as zeros but still yield accurate energy approximation. Such techniques can also be combined parallel computing resources obtain further efficiency and scalability. This work focuses on distributed memory implementation of a method for second Mo̷ller-Plesset (MP2) theory. only has single threshold control dropping terms accuracy different kernels algorithm. The process partitioning strategy message passing interface (MPI) are discussed. particular, algorithm relies fixed sparsity pattern matrix multiplication corresponding conjugate gradient solver, which exhibits almost linear scaling both strong weak analyses. Numerical experiments range molecules, including chains molecules 2 3-dimensional characters, reported. For example, 32 MPI ranks, this MP2 calculate vancomycin def2-TZVP basis within 0.003% (10–6.5 threshold) half an hour, where same problem is unfeasible solve sequential or pure shared implementations.

Language: Английский

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SOS1-RSX-QIDH: A spin-opposite-scaled range-separated-exchange quadratic-integrand double-hybrid density functional

The Journal of Chemical Physics, Journal Year: 2023, Volume and Issue: 159(23)

Published: Dec. 15, 2023

We develop and validate the SOS1-RSX-QIDH density functional, a one-parameter spin-opposite-scaled variant of range-separated-exchange quadratic-integrand double-hybrid (RSX-QIDH) model. By entering into family spin-biased double hybrids, this new functional benefits from an improved computational scaling that rivals with one still conserving accuracy its RSX-QIDH version. As part latter family, is well-adapted to treat molecular systems are particularly prone self-interaction errors in their ground excited states. In particular, we show model good compromise ground-state problems dealing kinetics has real added value when applied evaluation excited-state properties equilibrium out-of-equilibrium complexes. Even if hybrids recognized strongly underestimate noncovalent interactions, notice recommend coupling nonlocal van der Waals potential, combination here proved compete best density-functional approximations currently use.

Language: Английский

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Computed versus experimental energy barriers in solution: Influence of the type of the density functional approximation

Journal of Computational Chemistry, Journal Year: 2024, Volume and Issue: 45(27), P. 2284 - 2293

Published: June 7, 2024

Mechanistic investigations at the density functional theory level of organic and organometallic reactions in solution are now broadly accessible routinely implemented to complement experimental investigations. The selection an appropriate among plethora developed ones is first challenge on way reliable energy barrier calculations. To provide guidelines for choice initial computational level, performances commonly used non-empirical (PBE, PBE0, PBE0-DH) empirical functionals (BLYP, B3LYP, B2PLYP) were evaluated relative activation enthalpies. Most reactivity databases assess primarily based high calculations, here a set enthalpies performed selected from literature. As general trend, outperform ones. most accurate barriers obtained with hybrid PBE0 double-hybrid PBE0-DH functionals, both providing similar performance. Regardless under consideration, addition GD3-BJ dispersion correction does not enhance accuracy computed barriers.

Language: Английский

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How to search for and reveal a hidden intermediate? The ELF topological description of non-synchronicity in double proton transfer reactions under oriented external electric field

Journal of Molecular Modeling, Journal Year: 2024, Volume and Issue: 30(11)

Published: Oct. 4, 2024

Language: Английский

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Molecular Understanding and Practical In Silico Catalyst Design in Computational Organocatalysis and Phase Transfer Catalysis—Challenges and Opportunities

Molecules, Journal Year: 2023, Volume and Issue: 28(4), P. 1715 - 1715

Published: Feb. 10, 2023

Through the lens of organocatalysis and phase transfer catalysis, we will examine key components to calculate or predict catalysis-performance metrics, such as turnover frequency measurement stereoselectivity, via computational chemistry. The state-of-the-art tools available potential energy and, consequently, free energy, together with their caveats, be discussed examples from literature. various highlight challenges related mechanism, transition state theory, solvation involved in translating calculated barriers a metric stereoselectivity. Examples literature that validated theoretical models showcased. Lastly, relevance opportunity afforded by machine learning discussed.

Language: Английский

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A DFT and TD-DFT Study of Two Hydralazine Derivatives for Organic Solar Cells and Nonlinear Optical Applications

Journal of Chemistry, Journal Year: 2023, Volume and Issue: 2023, P. 1 - 12

Published: Dec. 8, 2023

In recent years, organic molecules have been the subject of in-depth research studies using in silico methods for their applications solar cells and photonic devices. This study reports a theoretical investigation cell (OSC) nonlinear optical (NLO) properties (E)-1-(phthalazin-1-yl)-1-[(pyridin-2-yl)ethylidene]hydralazine (PPEH) 1-[2-(1-(pyridine-3- yl)ethylidene)hydrazinyl]phthalazine (PEHP). The density functional theory (DFT) its time-dependent extension (TD-DFT) were employed with B2PLYP, M06-2X, BP86, CAM-B3LYP, ω B97-XD functionals, alongside def2-tzvp def2-tzvpp basis sets. Geometrical Frontier molecular orbital (FMO) analyses performed. Reactivity descriptors, open circuit voltage (Voc), energy driving force (∆EL−L), light harvesting efficiencies (LHEs), NLO susceptibilities, also computed discussed. results show that PEPH PPEH are good electron donor materials as they possess high FMO energies, Vocs, ∆EL−Ls, LHEs. Moreover, both static first second hyperpolarizabilities well dynamic responses on average 10 times greater than those para-nitroaniline. exhibit such harmonic generation (SHG), electro-optic Pockels effect (EOPE), electric field-induced (EFISHG), Kerr (OKE). Indeed, these potential candidates applications. Findings from this work may further accelerate synthesis development green future.

Language: Английский

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Thermal isomerization of phenylazoindoles: Inversion or rotation? That is the question

International Journal of Quantum Chemistry, Journal Year: 2023, Volume and Issue: 123(24)

Published: March 27, 2023

Abstract Azoheteroarenes represent an attractive group of photochromes exhibiting a large structural variability and tunability photoswitching characteristics. The thermal back‐isomerization can proceed via inversion or rotation mechanisms, depending on the functionalization environment. However, distinction between two remains challenge for both experiment theory. Here, four experimentally fully characterized phenylazoindoles are studied to establish mechanism back‐reaction in solvent using density functional theory (DFT), spin‐flip time‐dependent (TD‐)DFT, mixed‐reference TD‐DFT, restricted ensemble Kohn–Sham approaches as well CASPT2 CCSD(T). While is consistently described by all methods, requires multireference including dynamic correlation. balanced description pathways becomes even more important which apparently affects mechanism. For present set, range‐separated functionals combined with continuum models appear be most consistent terms substitutional effects halftimes.

Language: Английский

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