Direct computation of parameters for accurate polarizable force fields

Verstraelen, Toon; Vandenbrande, Steven; Ayers, Paul W.

doi:10.1063/1.4901513

Cited by 34 publications

(70 citation statements)

References 148 publications

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“…Similar response kernels were also used in Atom-Condensed Kohn-Sham Density Functional Theory approximated to second order (ACKS2) by Verstraelen, Vandenbrande, and Ayers 49 , and in the fitting of atomic polarizabilities for polarizable force fields by Wang and Yang 50 . The second key component of our framework is to approximate the electrostatic potential of each occupied-virtual molecular orbital pair in two different ways: (a) as a potential of atomic charges (PAC); or (b) as a potential of atomic dipoles (PAD), where all charges or dipoles are located on QM atomic sites.…”

Section: Introductionmentioning

confidence: 99%

An Estimation of Hybrid Quantum Mechanical Molecular Mechanical Polarization Energies for Small Molecules Using Polarizable Force-Field Approaches

Huang

König

et al. 2017

J. Chem. Theory Comput.

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In this work, we report two polarizable molecular mechanics (polMM) force field models for estimating the polarization energy in hybrid quantum mechanical molecular mechanical (QM/MM) calculations. These two models, named the potential of atomic charges (PAC) and potential of atomic dipoles (PAD), are formulated from the ab initio quantum mechanical (QM) response kernels for the prediction of the QM density response to an external molecular mechanical (MM) environment (as described by external point charges). The PAC model is similar to fluctuating charge (FQ) models because the energy depends on external electrostatic potential values at QM atomic sites; the PAD energy depends on external electrostatic field values at QM atomic sites, resembling induced dipole (ID) models. To demonstrate their uses, we apply the PAC and PAD models to twelve small molecules, which are solvated by TIP3P water. The PAC model reproduces the QM/MM polarization energy with a R2 value of 0.71 for aniline (in 10,000 TIP3P water configurations) and 0.87 or higher for other eleven solute molecules, while the PAD model has a much better performance with R2 values of 0.98 or higher. The PAC model reproduces reference QM/MM hydration free energies for twelve solute molecules with a RMSD of 0.59 kcal/mol. The PAD model is even more accurate, with a much smaller RMSD of 0.12 kcal/mol, with respect to the reference. This suggests that polarization effects, including both local charge distortion and intramolecular charge transfer, can be well captured by induced dipole type models with proper parameterization.

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Section: Introductionmentioning

confidence: 99%

An Estimation of Hybrid Quantum Mechanical Molecular Mechanical Polarization Energies for Small Molecules Using Polarizable Force-Field Approaches

Huang

König

et al. 2017

J. Chem. Theory Comput.

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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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“…At the outset of this long term project, the ubiquitous atomic point charges (one on each nucleus) were replaced by nucleus-centred atomic multipole moments. This step is shared by other next-generation force fields such as AMOEBA [3], XED [4], SIBFA [5] and ACKS2 [6] and is driven by a clearly justified desire towards increasingly accurate electrostatics [7,8].…”

Section: Introductionmentioning

confidence: 99%

The prediction of topologically partitioned intra-atomic and inter-atomic energies by the machine learning method kriging

et al. 2016

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Direct computation of parameters for accurate polarizable force fields

Cited by 34 publications

References 148 publications

An Estimation of Hybrid Quantum Mechanical Molecular Mechanical Polarization Energies for Small Molecules Using Polarizable Force-Field Approaches

An Estimation of Hybrid Quantum Mechanical Molecular Mechanical Polarization Energies for Small Molecules Using Polarizable Force-Field Approaches

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

The prediction of topologically partitioned intra-atomic and inter-atomic energies by the machine learning method kriging

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