Effects of the dispersion interaction in liquid water (original) (raw)
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Modelling of dispersion and repulsion interactions in liquids
Journal of Molecular Structure: THEOCHEM, 1991
A hierarchy of useful expressions for evaluating the Gibbs free energy of dispersion and repulsion interactions in condensed media has been developed. The method is based on the approximate London and Born formulae for solute-solvent interactions. Five different approximations are presented ranging from the simple molecule-molecule type formula up to more advanced atomatom type expressions which take into account a uniform solvent distribution and specific solutesolvent molecular orientations. The quality of the method and the particular approximations have been tested on a wide series of solutes of various polarities and symmetries in different solvents. The nonadditivity of intermolecular dispersion and repulsion interactions is treated using structure-dependent atomic parameters. The derived formulae are compatible with continuum models of solvation.
The Journal of Chemical Physics, 2009
We present an extension of the TIP4P-QDP model, TIP4P-QDP-LJ, that is designed to couple changes in repulsive and dispersive nonbond interactions to changes in polarizability. Polarizability is intimately related to the dispersion component of classical force field models of interactions, and we explore the effect of incorporating this connection explicitly on properties along the liquid-vapor coexistence curve of pure water. Parametrized to reproduce condensed-phase liquid water properties at 298 K, the TIP4P-QDP-LJ model predicts density, enthalpy of vaporization, self-diffusion constant, and the dielectric constant at ambient conditions to about the same accuracy as TIP4P-QDP but shows remarkable improvement in reproducing the liquid-vapor coexistence curve. TIP4P-QDP-LJ predicts critical constants of T c = 623 K, c = 0.351 g / cm 3 , and P c = 250.9 atm, which are in good agreement with experimental values of T c = 647.1 K, c = 0.322 g / cm 3 , and P c = 218 atm, respectively. Applying a scaling factor correction ͑obtained by fitting the experimental vapor-liquid equilibrium data to the law of rectilinear diameters using a three-term Wegner expansion͒ the model predicts critical constants ͑T c = 631 K and c = 0.308 g / cm 3 ͒. Dependence of enthalpy of vaporization, self-diffusion constant, surface tension, and dielectric constant on temperature are shown to reproduce experimental trends. We also explore the interfacial potential drop across the liquid-vapor interface for the temperatures studied. The interfacial potential demonstrates little temperature dependence at lower temperatures ͑300-450 K͒ and significantly enhanced ͑exponential͒ dependence at elevated temperatures. Terms arising from the decomposition of the interfacial potential into dipole and quadrupole contributions are shown to monotonically approach zero as the temperature approaches the critical temperature. Results of this study suggest that self-consistently treating the coupling of phase-dependent polarizability with dispersion interactions in classical water force fields may be an important effect for the extension of polarizable water force fields to reproduce properties along the liquid-vapor coexistence envelope as well as near critical conditions. More importantly, the present study demonstrates the rather remarkable transferability of a water model parametrized to a single state point to other thermodynamic states. Further studies are recommended.
The Journal of Chemical Physics, 1996
The structure, dynamical, and electronic properties of liquid water utilizing different hybrid density functionals were tested within the plane wave framework of first-principles molecular dynamics simulations. The computational approach, which employs modified functionals with short-ranged Hartree-Fock exchange, was first tested in calculations of the structural and bonding properties of the water dimer and cyclic water trimer. Liquid water simulations were performed at the state point of 350 K at the experimental density. Simulations included three different hybrid functionals, a meta-functional, four gradient-corrected functionals, and the local density and Hartree-Fock approximations. It is found that hybrid functionals are superior in reproducing the experimental structure and dynamical properties as measured by the radial distribution function and self-diffusion constant when compared to the pure density functionals. The local density and Hartree-Fock approximations show strongly over-and understructured liquids, respectively. Hydrogen bond analysis shows that the hybrid functionals give slightly smaller average numbers of hydrogen bonds than pure density functionals but similar hydrogen bond populations. The average molecular dipole moments in the liquid from the three hybrid functionals are lower than those of the corresponding pure density functionals. † Part of the special issue "Michael L. Klein Festschrift".
A Molecular Density Functional Theory of Water
2016
Three dimensional implementations of liquid state theories offer an efficient alternative to computer simulations for the atomic-level description of aqueous solutions in complex environments. In this context, we present a (classical) molecular density functional theory (MDFT) of water that is derived from first principles and is based on two classical density fields, a scalar one, the particle density, and a vectorial one, the multipolar polarization density. Its implementa-tion requires as input the partial charge distribution of a water molecule and three measurable bulk properties, namely the structure factor and the k-dependent lon-gitudinal and transverse dielectric constants. It has to be complemented by a solute-solvent three-body term that reinforces tetrahedral order at short range. The approach is shown to provide the correct three-dimensional microscopic sol-vation profile around various molecular solutes, possibly possessing H-bonding sites, at a computer cost two-three...
Two exchange-correlation functionals compared for first-principles liquid water
Molecular Simulation, 2005
The first-principles description of liquid water using ab initio molecular dynamics (AIMD) based on Density Functional theory (DFT) has recently been found to require long equilibration times, giving too low diffusivities and a clear over-structuring of the liquid. In the light of these findings we compare here the room-temperature description offered by two different exchange correlation functionals: BLYP, the most popular for liquid water so far, and RPBE, a revision of the widely used PBE. We find for RPBE a less structured liquid with radial distribution functions closer to the experimental ones than the ones of BLYP. The diffusivity obtained with RPBE for heavy water is still 20% lower than the corresponding experimental value, but it represents a substantial improvement on the BLYP value, one order of magnitude lower than experiment. These characteristics and the hydrogen-bond (HB) network imperfection point to an effective temperature ∼3% lower than the actual simulation temperature for the RPBE liquid, as compared with BLYP's ∼17% deviation. The too long O-O average nearest-neighbor distance observed points to an excessively weak HB, possibly compensating more fundamental errors in the DFT description.
Molecular Density Functional Theory of Water
The Journal of Physical Chemistry Letters, 2013
Three-dimensional implementations of liquid-state theories offer an efficient alternative to computer simulations for the atomic-level description of aqueous solutions in complex environments. In this context, we present a (classical) molecular density functional theory (MDFT) of water that is derived from first principles and is based on two classical density fields, a scalar one, the particle density, and a vectorial one, the multipolar polarization density. Its implementation requires as input the partial charge distribution of a water molecule and three measurable bulk properties, namely, the structure factor and the k-dependent longitudinal and transverse dielectric constants. It has to be complemented by a solute−solvent threebody term that reinforces tetrahedral order at short-range. The approach is shown to provide the correct 3-D microscopic solvation profile around various molecular solutes, possibly possessing H-bonding sites, at a computer cost two to three orders of magnitude lower than with explicit simulations.
Structure, Dynamics, and Spectral Diffusion of Water from First-Principles Molecular Dynamics
The Journal of Physical Chemistry C, 2014
We have carried out first-principles Born−Oppenheimer molecular dynamics (BOMD) simulations of heavy water using density functional theory in conjunction with either empirical van der Waals (vdW) corrections or semilocal (van der Waals) exchange and correlation functionals. Specifically, gradient-corrected density functionals (BLYP), semiempirical vdW methods (BLYP-D2, BLYP-D3, PBE-D3, revPBE-D3), and vdW density functionals (DRSLL-PBE, DRSLL-optB88) are applied to evaluate their accuracy in describing the hydrogen-bonded network of heavy water. Ab initio trajectories are used to calculate structural and dynamical properties, with special emphasis on vibrational spectral diffusion and hydrogen bond dynamics. Our results show that inclusion of vdW interactions in DFT-GGA significantly affects the structure of liquid water and results in a faster diffusion. The combination of BLYP and revPBE functionals with the semiempirical vdW method of Grimme et al. [J. Chem. Phys. 2010, 132, 154104] and modified B88 functionals with the semilocal correlation functional according to M. Dion et al. [Phys. Rev. Lett. 2004, 92, 246401] provide the best agreement with experiments.
Balancing local order and long-ranged interactions in the molecular theory of liquid water
The Journal of Chemical Physics, 2007
A molecular theory of liquid water is identified and studied on the basis of computer simulation of the TIP3P model of liquid water. This theory would be exact for models of liquid water in which the intermolecular interactions vanish outside a finite spatial range, and therefore provides a precise analysis tool for investigating the effects of longer-ranged intermolecular interactions. We show how local order can be introduced through quasi-chemical theory. Long-ranged interactions are characterized generally by a conditional distribution of binding energies, and this formulation is interpreted as a regularization of the primitive statistical thermodynamic problem. These bindingenergy distributions for liquid water are observed to be unimodal. The gaussian approximation proposed is remarkably successful in predicting the Gibbs free energy and the molar entropy of liquid water, as judged by comparison with numerically exact results. The remaining discrepancies are subtle quantitative problems that do have significant consequences for the thermodynamic properties that distinguish water from many other liquids. The basic subtlety of liquid water is found then in the competition of several effects which must be quantitatively balanced for realistic results.
Molecular dynamics simulation of liquid water between two walls
Chemical Physics Letters, 1983
The structure, dynamical, and electronic properties of liquid water utilizing different hybrid density functionals were tested within the plane wave framework of first-principles molecular dynamics simulations. The computational approach, which employs modified functionals with short-ranged Hartree-Fock exchange, was first tested in calculations of the structural and bonding properties of the water dimer and cyclic water trimer. Liquid water simulations were performed at the state point of 350 K at the experimental density. Simulations included three different hybrid functionals, a meta-functional, four gradient-corrected functionals, and the local density and Hartree-Fock approximations. It is found that hybrid functionals are superior in reproducing the experimental structure and dynamical properties as measured by the radial distribution function and self-diffusion constant when compared to the pure density functionals. The local density and Hartree-Fock approximations show strongly over-and understructured liquids, respectively. Hydrogen bond analysis shows that the hybrid functionals give slightly smaller average numbers of hydrogen bonds than pure density functionals but similar hydrogen bond populations. The average molecular dipole moments in the liquid from the three hybrid functionals are lower than those of the corresponding pure density functionals. † Part of the special issue "Michael L. Klein Festschrift".