Gaussian Multipole Model (GMM)

Elking, Dennis M.; Cisneros, G. Andrés; Piquemal, Jean‐Philip; Darden, Thomas A.; Pedersen, Lee G.

doi:10.1021/ct900348b

Cited by 82 publications

(143 citation statements)

References 78 publications

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“…56,76–79,102,103 To account for the charge penetration effect, we replace each point charge with a smeared charge, which consists of a negative exponential charge density and a positive point charge at the atomic center. 56 The net effect of smeared charges increases the strength of electrostatic interactions at the short range.…”

Section: Resultsmentioning

confidence: 99%

Directional Dependence of Hydrogen Bonds: A Density-Based Energy Decomposition Analysis and Its Implications on Force Field Development

Zhou

et al. 2011

J. Chem. Theory Comput.

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One well-known shortcoming of widely-used biomolecular force fields is the description of the directional dependence of hydrogen bonding (HB). Here we aim to better understand the origin of this difficulty and thus provide some guidance for further force field development. Our theoretical approaches center on a novel density-based energy decomposition analysis (DEDA) method [J. Chem. Phys., 131, 164112 (2009)], in which the frozen density energy is variationally determined through constrained search. This unique and most significant feature of DEDA enables us to find that the frozen density interaction term is the key factor in determining the HB orientation, while the sum of polarization and charge-transfer components shows very little HB directional dependence. This new insight suggests that the difficulty for current non-polarizable force fields to describe the HB directional dependence is not due to the lack of explicit polarization or charge-transfer terms. Using the DEDA results as reference, we further demonstrate that the main failure coming from the atomic point charge model can be overcome largely by introducing extra charge sites or higher order multipole moments. Among all the electrostatic models explored, the smeared charge distributed multipole model (up to quadrupole), which also takes account of charge penetration effects, gives the best agreement with the corresponding DEDA results. Meanwhile, our results indicate that the van der Waals interaction term needs to be further improved to better model directional hydrogen bonding.

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Section: Resultsmentioning

confidence: 99%

Directional Dependence of Hydrogen Bonds: A Density-Based Energy Decomposition Analysis and Its Implications on Force Field Development

Zhou

et al. 2011

J. Chem. Theory Comput.

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“…For example, we’ve described DFTB2 as using a Mulliken partitioning, but some have chosen to use CM3 charge mappings in their post-SCF analysis [71]. We have chosen to use is a constrained electrostatic fitting procedure [63,67,72–76]. The mathematical details of this procedure are fully presented in Ref.…”

Section: Methodsmentioning

confidence: 99%

Density-functional expansion methods: grand challenges

Giese

York

2012

Theor Chem Acc

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We discuss the source of errors in semiempirical density functional expansion (VE) methods. In particular, we show that VE methods are capable of well-reproducing their standard Kohn-Sham density functional method counterparts, but suffer from large errors upon using one or more of these approximations: the limited size of the atomic orbital basis, the Slater monopole auxiliary basis description of the response density, and the one- and two-body treatment of the core-Hamiltonian matrix elements. In the process of discussing these approximations and highlighting their symptoms, we introduce a new model that supplements the second-order density-functional tight-binding model with a self-consistent charge-dependent chemical potential equalization correction; we review our recently reported method for generalizing the auxiliary basis description of the atomic orbital response density; and we decompose the first-order potential into a summation of additive atomic components and many-body corrections, and from this examination, we provide new insights and preliminary results that motivate and inspire new approximate treatments of the core-Hamiltonian.

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“…Fortunately, there has been much interest in the use of auxiliary basis sets in the context of traditional ab initio methods [25][26][27][28][29][30] and polarizable density-fitted force fields, [31][32][33][34] whose ideas we can draw upon. In the context of Kohn-Sham potential energy expansion methods, however, we seek to tailor the methodology to allow for the precomputation of these "mapping coefficients" on numerical splines, in a manner analogous to SCC-DFTB.…”

Section: Introductionmentioning

confidence: 99%

Density-functional expansion methods: Generalization of the auxiliary basis

Giese¹,

York²

2011

The Journal of Chemical Physics

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The formulation of density-functional expansion methods is extended to treat the second and higherorder terms involving the response density and spin densities with an arbitrary single-center auxiliary basis. The two-center atomic orbital products are represented by the auxiliary functions centered about those two atoms, and the mapping coefficients are determined from a local constrained variational procedure. This two-center variational procedure allows the mapping coefficients to be pretabulated and splined as a function of internuclear separation for efficient look up. The splines of mapping coefficients have a range no longer than that of the overlap integrals, and the auxiliary density appears as a single point-multipole expansion to all nonoverlapping atoms, thus allowing for the trivial implementation of a linear-scaling algorithm. The method is tested using Gaussian multipole expansions, and the effect of angular and radial completeness is explored. Several auxiliary basis sets are parametrized and compared to an auxiliary basis analogous to that used in the selfconsistent-charge density-functional tight-binding model, and the method is demonstrated to greatly improve the representation of the density response with respect to a reference expansion model that does not use an auxiliary basis.

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Gaussian Multipole Model (GMM)

Cited by 82 publications

References 78 publications

Directional Dependence of Hydrogen Bonds: A Density-Based Energy Decomposition Analysis and Its Implications on Force Field Development

Directional Dependence of Hydrogen Bonds: A Density-Based Energy Decomposition Analysis and Its Implications on Force Field Development

Density-functional expansion methods: grand challenges

Density-functional expansion methods: Generalization of the auxiliary basis

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