ACKS2: Atom-condensed Kohn-Sham DFT approximated to second order

Verstraelen, Toon; Ayers, Paul W.; Speybroeck, Véronique Van; Waroquier, Michel

doi:10.1063/1.4791569

Cited by 103 publications

(139 citation statements)

References 154 publications

(235 reference statements)

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“…Second, the good geometry dependence of atomic charges in EEM [39] is not valid for small displacements of the nuclei. This is reminiscent of the limitations of EEM for the description of the dipole polarizability [40,15,43,24,16] and suggests that EEM fails to describe any type of electronic linear response. An interesting topic of future research would therefore be the reproduction of dipole derivatives with recent generalizations of EEM that fix the dipole polarizability weaknesses, e.g.…”

Section: Discussionmentioning

confidence: 99%

“…An interesting topic of future research would therefore be the reproduction of dipole derivatives with recent generalizations of EEM that fix the dipole polarizability weaknesses, e.g. SQE [15] or ACKS2 [16].…”

Section: Discussionmentioning

confidence: 99%

“…Over the past 27 years, EEM strongly influenced related areas, such as in-silico screening [6], chemical reactivity descriptors [7,8,9] and empirical models for molecular potential energy surfaces, hereafter referred to as (polarizable and possibly reactive) force fields [10,11,12,13,14,15,16]. Extensive calibration studies have demonstrated the accuracy of atomic charges and the parameter transferability of EEM [17,18,19,20,21,22,14,23] and its recent generalizations, the Split-Charge Equilibration (SQE) [15,24,25,26] and Atom-Condensed Kohn-Sham approximated to Second order (ACKS2) [16].…”

Section: One Of Its Modern Incarnations Is the Electronegativity Equamentioning

confidence: 99%

“…Justifications and a detailed description of the underlying physics can be found elsewhere [4,12,31,16]. The molecular energy for a system with N atoms is approximated to second order in the atomic charges, E({q}) = χ χ χ q q q + 1 2 q q q η η ηq q q,…”

Section: Key Spectroscopic Quantities In Eemmentioning

confidence: 99%

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Can the electronegativity equalization method predict spectroscopic properties?

Verstraelen

Bultinck

2015

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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The electronegativity equalization method is classically used as a method allowing the fast generation of atomic charges using a set of calibrated parameters and provided knowledge of the molecular structure. Recently, it has started being used for the calculation of other reactivity descriptors and for the development of polarizable and reactive force fields. For such applications, it is of interest to know whether the method, through the inclusion of the molecular geometry in the Taylor expansion of the energy, would also allow sufficiently accurate predictions of spectroscopic data. In this work, relevant quantities for IR spectroscopy are considered, namely the dipole derivatives and the Cartesian Hessian. Despite careful calibration of parameters for this specific task, it is shown that the current models yield insufficiently accurate results.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: One Of Its Modern Incarnations Is the Electronegativity Equamentioning

confidence: 99%

Section: Key Spectroscopic Quantities In Eemmentioning

confidence: 99%

See 2 more Smart Citations

Can the electronegativity equalization method predict spectroscopic properties?

Verstraelen

Bultinck

2015

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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“…To ameliorate this issue, we have recently incorporated atom-condensed Kohn-Sham DFT approximated to second order (ACKS2) in ReaxFF. 136,137 ACKS2 is an extension of EEM that penalises long-range charge transfer with a bondpolarisation energy, in line with the split-charge equilibration (SQE) model. 138 The bond polarisability is a function of interatomic distance, which slightly increases beyond the equilibrium bond length but then quickly decays to zero, effectively enforcing fragment neutrality.…”

Section: Future Developments and Outlookmentioning

confidence: 99%

The ReaxFF reactive force-field: development, applications and future directions

et al. 2016

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The reactive force-field (ReaxFF) interatomic potential is a powerful computational tool for exploring, developing and optimizing material properties. Methods based on the principles of quantum mechanics (QM), while offering valuable theoretical guidance at the electronic level, are often too computationally intense for simulations that consider the full dynamic evolution of a system. Alternatively, empirical interatomic potentials that are based on classical principles require significantly fewer computational resources, which enables simulations to better describe dynamic processes over longer timeframes and on larger scales. Such methods, however, typically require a predefined connectivity between atoms, precluding simulations that involve reactive events. The ReaxFF method was developed to help bridge this gap. Approaching the gap from the classical side, ReaxFF casts the empirical interatomic potential within a bond-order formalism, thus implicitly describing chemical bonding without expensive QM calculations. This article provides an overview of the development, application, and future directions of the ReaxFF method. INTRODUCTIONAtomistic-scale computational techniques provide a powerful means for exploring, developing and optimizing promising properties of novel materials. Simulation methods based on quantum mechanics (QM) have grown in popularity over recent decades due to the development of user-friendly software packages making QM level calculations widely accessible. Such availability has proved particularly relevant to material design, where QM frequently serves as a theoretical guide and screening tool. Unfortunately, the computational cost inherent to QM level calculations severely limits simulation scales. This limitation often excludes QM methods from considering the dynamic evolution of a system, thus hampering our theoretical understanding of key factors affecting the overall behaviour of a material. To alleviate this issue, QM structure and energy data are used to train empirical force fields that require significantly fewer computational resources, thereby enabling simulations to better describe dynamic processes. Such empirical methods, including reactive force-field (ReaxFF), 1 trade accuracy for lower computational expense, making it possible to reach simulation scales that are orders of magnitude beyond what is tractable for QM.Atomistic force-field methods utilise empirically determined interatomic potentials to calculate system energy as a function of atomic positions. Classical approximations are well suited for nonreactive interactions, such as angle-strain represented by harmonic potentials, dispersion represented by van der Waals potentials and Coulombic interactions represented by various polarisation schemes. However, such descriptions are inadequate for modelling changes in atom connectivity (i.e., for modelling chemical reactions as bonds break and form). This motivates the

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Charge Transfer and Polarization in Force Fields: AnAb InitioApproach Based on the (Atom‐Condensed) Kohn–Sham Equations, Approximated by Second‐Order Perturbation Theory About the Reference Atoms (ACKS2)

Ayers¹

2022

Conceptual Density Functional Theory

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ACKS2: Atom-condensed Kohn-Sham DFT approximated to second order

Cited by 103 publications

References 154 publications

Can the electronegativity equalization method predict spectroscopic properties?

Can the electronegativity equalization method predict spectroscopic properties?

The ReaxFF reactive force-field: development, applications and future directions

Charge Transfer and Polarization in Force Fields: AnAb InitioApproach Based on the (Atom‐Condensed) Kohn–Sham Equations, Approximated by Second‐Order Perturbation Theory About the Reference Atoms (ACKS2)

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