The Pluses and Minuses of Mapping Atomic Charges to Electrostatic Potentials

Francl, Michelle; Chirlian, Lisa Emily

doi:10.1002/9780470125915.ch1

Cited by 62 publications

(57 citation statements)

References 32 publications

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“…This results in a large sensitivity of ESP fitted charges to small influences such as the choice of the grid points, the orientation of the molecule with respect to the grid, and (as we also observe here) the molecular geometry. 34 Only the Hirshfeld-I scheme has a good performance in both benchmarks: these charges both reproduce the dipole moments and are robust with respect to geometrical changes. With the Hirshfeld-I scheme it is indeed possible to rationalize protein electrostatics in terms of atomic charges: these charges give a quantitatively correct picture of the ESP and are suitable for a chemical interpretation.…”

Section: 62mentioning

confidence: 99%

“…Among the most popular schemes, we have Mulliken population analysis, 29 Lowdin population analysis, 30 Hirshfeld partitioning, 31 Natural population analysis, 27 Bader's AIM scheme, 32 and Hirshfeld-I partitioning. 33 In addition to the AIM schemes, atomic charges can also be fitted to reproduce the electrostatic potential around a molecule, 34 with for example the Merz-Kollman Although ESP fitted charges can accurately reproduce the molecular multipole expansion and electrostatic interactions between molecules, they are often showing unexpected trends that make no chemical sense. 34 For the direct interpretation of the atomic charges, or for the calibration charge equilibration models, such unexplainable trends are prohibitive.…”

Section: Introductionmentioning

confidence: 99%

“…33 In addition to the AIM schemes, atomic charges can also be fitted to reproduce the electrostatic potential around a molecule, 34 with for example the Merz-Kollman Although ESP fitted charges can accurately reproduce the molecular multipole expansion and electrostatic interactions between molecules, they are often showing unexpected trends that make no chemical sense. 34 For the direct interpretation of the atomic charges, or for the calibration charge equilibration models, such unexplainable trends are prohibitive. In addition to charges derived from QM computations, one can also compute atomic charges with charge equilibration models such as the Electronegativity Equalization Method 38,39 (EEM) and the Split Charge Equilibration 40 (SQE).…”

Section: Introductionmentioning

confidence: 99%

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Assessment of Atomic Charge Models for Gas-Phase Computations on Polypeptides

Verstraelen

Pauwels

Proft³

et al. 2012

J. Chem. Theory Comput.

127

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Abstract. The concept of the atomic charge is extensively used to model the electrostatic properties of proteins. Atomic charges are not only the basis for the electrostatic energy term in biomolecular force fields, but are also derived from quantum mechanical (QM) computations on protein fragments to get more insight into their electronic structure. Unfortunately there are many atomic charge schemes which lead to significantly different results, and it is not trivial to determine which scheme is most suitable for biomolecular studies. Therefore, we present an extensive methodological benchmark using a selection of atomic charge schemes (Mulliken, Natural, RESP, Hirshfeld-I, EEM and SQE) applied to two sets of penta-alanine conformers. Our analysis clearly shows that Hirshfeld-I charges offer the best compromise between transferability (robustness with respect to conformational changes) and the ability to reproduce electrostatic properties of the penta-alanine. The benchmark also considers two charge equilibration models (EEM and SQE), which both clearly fail to describe the locally charged moieties in the zwitterionic form of penta-alanine. This issue is analyzed in detail because charge equilibration models are computationally much more attractive than the Hirshfeld-I scheme. Based on the latter analysis, a straightforward extension of the SQE model is proposed, SQE+Q 0 , that is suitable to describe biological systems bearing many locally charged functional groups.

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Section: 62mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Assessment of Atomic Charge Models for Gas-Phase Computations on Polypeptides

Verstraelen

Pauwels

Proft³

et al. 2012

J. Chem. Theory Comput.

127

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“…This can be done in a number of ways 16,17,18,19 , and it is not a trivial problem 20 , and the fit can be carried out with further constraints, such as reproducing the molecular dipole moment. In addition, the calculation of the quantum mechanical ESP used as basis for the determination of point charges can be done with different approximations and level of theory.…”

Section: Electrostatics : Atomic Point Chargesmentioning

confidence: 99%

“…This must be viewed in light of the fact that ESP-charges sometimes vary significantly with molecular conformation 20 . Finally, no general trends can be discovered with respect to how well the methods apportion charges to different atom types.…”

mentioning

confidence: 99%

Force Fields and Point Charges for Crystal Structure Modeling

Svärd

Rasmuson

2009

Ind. Eng. Chem. Res.

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ABSTRACT. Molecular simulation is increasingly used by chemical engineers and industrial chemists in process and product development. In particular, the possibility to predict the structure and stability of potential polymorphs of a substance is of tremendous interest to the pharmaceutical and specialty chemicals industry. Molecular mechanics modelling relies on the use of parameterized force fields and methods of assigning point charges to the atoms in the molecules. In commercial molecular simulation software a wide variety of such combinations are available, and there is a need for critical assessment of the capabilities of the different alternatives.In the present work, the performance of several molecular mechanics force fields combined with different methods for the assignment of atomic point charges have been examined with regard to their ability to calculate absolute crystal lattice energies and their capacity to identify the experimental structure as a minimum on the potential energy hypersurface. Seven small, aromatic mono-molecular crystalline compounds are used in the evaluation. It is found that the majority of the examined methods cannot be used to reliably predict absolute lattice energies. The most promising results were obtained with the Pcff force field using integral charges, and the Dreiding force field using Gasteiger charges, both of which performed with an accuracy of the same order of magnitude as the variations in experimental lattice energies. Overall, it has been observed that the best results are achieved if the same force field method is used to relax the crystal structure and calculate the energy, and to optimize and calculate the energy of the gas phase molecule used for the correction for changes in molecular geometry. The Pcff and Compass force fields with integral charges have been found to predict relaxed structures closest to the experimental ones.In addition, five different methods for determining point charges fitted to the electrostatic potential (ESP-charges), available in the same software, have been evaluated. For each method, the molecular geometries of ten small, organic molecules were optimized, and ESP-charges calculated and analyzed for linear correlation with a set of reference charges of an accepted standard method, HF/6-31G*. Dmol-3 gives charges that correlate well with the reference charge.The charges from Vamp are not linearly scalable to the HF/6-31G*-level, which is attributed partly to the geometry optimization but mainly to the calculation of the ESP and the subsequent charge fit.

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Chemical Response Functions in (Quasi‐)Degenerate States

Bultinck¹,

Cárdenas²

2022

Conceptual Density Functional Theory

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The Pluses and Minuses of Mapping Atomic Charges to Electrostatic Potentials

Cited by 62 publications

References 32 publications

Assessment of Atomic Charge Models for Gas-Phase Computations on Polypeptides

Assessment of Atomic Charge Models for Gas-Phase Computations on Polypeptides

Force Fields and Point Charges for Crystal Structure Modeling

Chemical Response Functions in (Quasi‐)Degenerate States

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