scholarly journals Dielectric response with short-ranged electrostatics

2020 ◽  
Vol 117 (33) ◽  
pp. 19746-19752
Author(s):  
Stephen J. Cox
Keyword(s):  
Dielectric Response ◽  
Electrostatic Interactions ◽  
Mean Field ◽  
Periodic Boundary Conditions ◽  
Liquid Structure ◽  
Water Model ◽  
Dipolar Interactions ◽  
Polar Liquids ◽  
Ability To Act ◽  
Local Molecular Field Theory

The dielectric nature of polar liquids underpins much of their ability to act as useful solvents, but its description is complicated by the long-ranged nature of dipolar interactions. This is particularly pronounced under the periodic boundary conditions commonly used in molecular simulations. In this article, the dielectric properties of a water model whose intermolecular electrostatic interactions are entirely short-ranged are investigated. This is done within the framework of local molecular-field theory (LMFT), which provides a well-controlled mean-field treatment of long-ranged electrostatics. This short-ranged model gives a remarkably good performance on a number of counts, and its apparent shortcomings are readily accounted for. These results not only lend support to LMFT as an approach for understanding solvation behavior, but also are relevant to those developing interaction potentials based on local descriptions of liquid structure.

A thermodynamic model of hemoglobin suitable for physiological applications

1990 ◽  
Vol 258 (3) ◽  
pp. C563-C577 ◽  
Author(s):  
T. Yoshida ◽  
M. Dembo
Keyword(s):  
Binding Sites ◽  
Electrostatic Interactions ◽  
Mean Field ◽  
Quantitative Model ◽  
Confidence Limits ◽  
Efficient Computation ◽  
Ligand Binding Sites ◽  
The Mean ◽  
Field Formalism ◽  
Good Agreement

We propose a quantitative model of the thermodynamics of hemoglobin in contact with its five major ligands (O2, CO2, Cl-, 2,3-bisphosphoglycerate, and H+). Our model incorporates the two-state formalism of J. Monod, J. Wyman, and J.P. Changeux (J. Mol. Biol. 12: 88-118, 1965) for treatment of quanternary transitions and also the mean field formalism of K. Linderstrom-Lang (C. R. Trav. Lab. Carlsberg Ser. Chim. 15: 1-30, 1924) for treatment of electrostatic interactions. On the basis of this approach, we develop an algorithm for the efficient computation of observable quantities, such as the occupancy of various ligand binding sites, and an objective statistical procedure for determining both maximum likelihood values and confidence limits of all the intrinsic thermodynamic parameters of hemoglobin. Finally, we show that the predictions of our theory are in good agreement with independent experimental observations.

A refined polarizable water model for the coarse-grained MARTINI force field with long-range electrostatic interactions

2017 ◽  
Vol 146 (5) ◽  
pp. 054501 ◽  
Author(s):  
Julian Michalowsky ◽  
Lars V. Schäfer ◽  
Christian Holm ◽  
Jens Smiatek
Keyword(s):  
Force Field ◽  
Long Range ◽  
Electrostatic Interactions ◽  
Coarse Grained ◽  
Water Model ◽  
Martini Force Field

Bose Liquid Mean-Field Theory with Application to HeI

2019 ◽  
Vol 26 (02) ◽  
pp. 1950005
Author(s):  
Jan Maćkowiak
Keyword(s):  
Field Theory ◽  
Heat Capacity ◽  
Temperature Dependence ◽  
Mean Field Theory ◽  
Mean Field ◽  
Liquid Structure ◽  
Experimental Plot ◽  
Bose Liquid ◽  
Ordered Motion ◽  
Good Agreement

A mean-field theory is developed for a Bose liquid enclosed in a large vessel 𝒱. In accord with liquid structure concepts of Mitus et al., the liquid in 𝒱 is assumed to consist of adjacent macroscopic subregions Λk. In each subregion the bosons perform a locally ordered motion with prevailing orientation k + x, which varies randomly when passing from one subregion to another. |k| is constant, whereas temperature dependence of |x| is governed by a mean-field theory (MFT). The theory is applied to simulate HeI heat capacity CV (T) at T > Tλ = 2.17 K and CV (T) singularity at [Formula: see text]. The MFT numerical heat capacity Cn(T) = ΔE/ΔT exhibits behaviour characteristic of a singularity at [Formula: see text]: rapid increase with decreasing ΔT. Apart from [Formula: see text], good agreement of Cn(T) with CV(T) experimental plot is also found above Tλ, at T ∊ (Tλ, 3K].

Simplifying Primitive Equations: Rotating Shallow-Water Models and their Properties

2018 ◽  
Author(s):  
Vladimir Zeitlin
Keyword(s):  
Conservation Laws ◽  
Shallow Water ◽  
Variational Principles ◽  
Mean Field ◽  
Tangent Plane ◽  
Primitive Equations ◽  
Water Model ◽  
Shallow Water Model ◽  
Shallow Water Models ◽  
Rotating Shallow Water

In this chapter, one- and two-layer versions of the rotating shallow-water model on the tangent plane to the rotating, and on the whole rotating sphere, are derived from primitive equations by vertical averaging and columnar motion (mean-field) hypothesis. Main properties of the models including conservation laws and wave-vortex dichotomy are established. Potential vorticity conservation is derived, and the properties of inertia–gravity waves are exhibited. The model is then reformulated in Lagrangian coordinates, variational principles for its one- and two-layer version are established, and conservation laws are reinterpreted in these terms.

Dielectric Response of a Chain of Disordered Polarizable Spheres: Numerical Simulation and Theory

1991 ◽  
Vol 253 ◽  
Author(s):  
Pedro VillaseiÑor-Gonzalez ◽  
Cecilia Noguez ◽  
Ruben G. Barrera
Keyword(s):  
Numerical Simulation ◽  
Dielectric Response ◽  
Linear Equations ◽  
Periodic Boundary Conditions ◽  
Dimensional System ◽  
Effective Response ◽  
Static Approximation ◽  
One Dimensional ◽  
Induced Dipole ◽  
A Chain

ABSTRACTWe applied to a one-dimensional system (1D) a recently developed diagrammatic formalism, in order to calculate the effective dielectric response of a chain of polarizable spheres embeded in an homogeneous host. The effective response is calculated within the dipolar, quasi-static approximation, through the summation of selected classes of diagrams. We compared our results with a numerical simulation, where the position of each sphere was generated at random and the induced dipole moment of each sphere was calculated by solving a set of linear equations through matrix inversion and using periodic boundary conditions.

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