A generating equation for mixing rules and two new mixing rules for interatomic potential energy parameters

Al-Matar, Ali; Rockstraw, David A.

doi:10.1002/jcc.10418

Cited by 85 publications

(47 citation statements)

References 24 publications

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“…The buffered 14-7 vdW potential, and particularly the effect of a combining rule on heteroatomic vdW interactions in differing environments, is a likely impediment to improved accuracy. 139 …”

Section: Resultsmentioning

confidence: 99%

Polarizable Atomic Multipole-Based Molecular Mechanics for Organic Molecules

Ren

Ponder

2011

J. Chem. Theory Comput.

436

690

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An empirical potential based on permanent atomic multipoles and atomic induced dipoles is reported for alkanes, alcohols, amines, sulfides, aldehydes, carboxylic acids, amides, aromatics and other small organic molecules. Permanent atomic multipole moments through quadrupole moments have been derived from gas phase ab initio molecular orbital calculations. The van der Waals parameters are obtained by fitting to gas phase homodimer QM energies and structures, as well as experimental densities and heats of vaporization of neat liquids. As a validation, the hydrogen bonding energies and structures of gas phase heterodimers with water are evaluated using the resulting potential. For 32 homo- and heterodimers, the association energy agrees with ab initio results to within 0.4 kcal/mol. The RMS deviation of hydrogen bond distance from QM optimized geometry is less than 0.06 Å. In addition, liquid self-diffusion and static dielectric constants computed from molecular dynamics simulation are consistent with experimental values. The force field is also used to compute the solvation free energy of 27 compounds not included in the parameterization process, with a RMS error of 0.69 kcal/mol. The results obtained in this study suggest the AMOEBA force field performs well across different environments and phases. The key algorithms involved in the electrostatic model and a protocol for developing parameters are detailed to facilitate extension to additional molecular systems.

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Section: Resultsmentioning

confidence: 99%

Polarizable Atomic Multipole-Based Molecular Mechanics for Organic Molecules

Ren

Ponder

2011

J. Chem. Theory Comput.

436

690

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“…Hexane-water cross interaction parameters are determined using often-used Lorentz-Berthelot (LB) combining rules. We acknowledge that the use of the LB combining rule is an approximation that has come under scrutiny in the recent literature [34-37]. There is no a priori reason to implement this particular combining rule (with ample evidence in the literature suggesting that it does not provide the most accurate description of cross-interactions, or off-diagonal non-bond dispersion interactions in the case of noble gas mixtures [34] and polar compounds in the context of hydration free energies[36]; however, for the present study, we apply this combining rule as it is a common practice, and within the context of this approximation, we consider the properties of the heterogeneous systems defined here, acknowledging that the combining rule is a potential source of error between computed properties and experiment.…”

Section: Force Fields and Computational Methodsmentioning

confidence: 99%

Phase-transfer energetics of small-molecule alcohols across the water–hexane interface: Molecular dynamics simulations using charge equilibration models

Bauer

Zhong

Meninger

et al. 2011

Journal of Molecular Graphics and Modelling

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We study the water-hexane interface using molecular dynamics (MD) and polarizable charge equilibration (CHEQ) force fields. Bulk densities for TIP4P-FQ water and hexane, 1.0086±0.0002 g/cm 3 and 0.6378±0.0001 g/cm 3 , demonstrate excellent agreement with experiment. Interfacial width and interfacial tension are consistent with previously reported values. The in-plane component of the dielectric permittivity (ε ∥ ) for water is shown to decrease from 81.7±0.04 to unity, transitioning longitudinally from bulk water to bulk hexane. ε ∥ for hexane reaches a maximum in the interface, but this term represents only a small contribution to the total dielectric constant (as expected for a non-polar species). Structurally, net orientations of the molecules arise in the interfacial region such that hexane lies slightly parallel to the interface and water reorients to maximize hydrogen bonding. Interfacial potentials due to contributions of the water and hexane are calculated to be -567.9±0.13mV and 198.7±0.01mV, respectively, giving rise to a total potential in agreement with the range of values reported from previous simulations of similar systems. Potentials of mean force (PMF) calculated for methanol, ethanol, and 1-propanol for the transfer from water to hexane indicate an interfacial free energy minimum, corresponding to the amphiphilic nature of the molecules. The magnitudes of transfer free energies were further characterized from the solvation free energies of alcohols in water and hexane using thermodynamic integration. This analysis shows that solvation free energies for alcohols in hexane are 0.2-0.3 kcal/mol too unfavorable, whereas solvation of alcohols in water is approximately 1 kcal/mol too favorable. For the pure hexane-water interfacial simulations, we observe a monotonic decrease of the water dipole moment to near-vacuum values. This suggests that the electrostatic component of the desolvation free energy is not as severe for polarizable models than for fixedcharge force fields. The implications of such behavior pertain to the modeling of polar and charged solutes in lipidic environments.

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“…Hagler type, which should provide a better overall description of interactions between a broader range of systems [168,169]:…”

Section: Benchmarking the Acetonitrile Liquid Pseudo-structurementioning

confidence: 99%