Monte Carlo intrinsic surfaces and density profiles for liquid surfaces

Tarazona, P.; Chacón, Enrique

doi:10.1103/physrevb.70.235407

Cited by 85 publications

(86 citation statements)

References 39 publications

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“…That number of particles per unit area is transformed in a local film thickness assuming that the surface z = ξ GS (R) separates a uniform density of the liquid phase from a uniform density of the vapor phase. Therefore, the q = 0 Fourier components are directly given from the position of the particles [11], aŝ…”

Section: Appendix: Model Methods and Gibbs Surface Resultsmentioning

confidence: 99%

“…Their theoretical description [4] is based on effective Hamiltonians H[ξ ], modeled as functionals of ξ (R), following the capillary wave theory (CWT) for free liquid surfaces [5][6][7][8] or from simple density-functional models [9]. In this paper we present a fully quantitative description of H[ξ ] for a realistic model: a Lennard-Jones fluid adsorbed on a planar wall, analyzed with the intrinsic sampling method (ISM) for the shape of a fluctuating fluid interface [10,11]. Our results provide a proof of principle for the method to bridge the gap between computer simulations at molecular scale and the mesoscopic behavior of these systems with quantitative accuracy.…”

Section: Introductionmentioning

confidence: 99%

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Mesoscopic Hamiltonian for the fluctuations of adsorbed Lennard-Jones liquid films

et al. 2015

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We use Monte Carlo simulations of a Lennard-Jones fluid adsorbed on a short-range planar wall substrate to study the fluctuations in the thickness of the wetting layer, and we get a quantitative and consistent characterization of their mesoscopic Hamiltonian, H [ξ ]. We have observed important finite-size effects, which were hampering the analysis of previous results obtained with smaller systems. The results presented here support an appealing simple functional form for H[ξ ], close but not exactly equal to the theoretical nonlocal proposal made on the basis a generic density-functional analysis by Parry and coworkers. We have analyzed systems under different wetting conditions, as a proof of principle for a method that provides a quantitative bridge between the molecular interactions and the phenomenology of wetting films at mesoscopic scales.

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Section: Appendix: Model Methods and Gibbs Surface Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mesoscopic Hamiltonian for the fluctuations of adsorbed Lennard-Jones liquid films

et al. 2015

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“…These algorithms eliminate the averaging effect of thermal fluctuations. 30,31 This approach, and similar ones, [32][33][34] have been applied to a number of fluid interfaces; simple fluids, 35 water, 36,37 alkali fluids, 38 oil-water interfaces, 32, 39-41 hydrophilic interfaces, 42 and molten salts. 43 The intrinsic profile offers a higher level of resolution of the interface, and, unlike the mean profiles, it is independent of the interfacial cross sectional area used in the simulations.…”

Section: Introductionmentioning

confidence: 99%

The structure of ionic aqueous solutions at interfaces: An intrinsic structure analysis

Bresme

Chacón

Tarazona

et al. 2012

The Journal of Chemical Physics

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We investigate the interfacial structure of ionic solutions consisting of alkali halide ions in water at concentrations in the range 0.2-1.0 molal and at 300 K. Combining molecular dynamics simulations of point charge ion models and a recently introduced computational approach that removes the averaging effect of interfacial capillary waves, we compute the intrinsic structure of the aqueous interface. The interfacial structure is more complex than previously inferred from the analysis of mean profiles. We find a strong alternating double layer structure near the interface, which depends on the cation and anion size. Relatively small changes in the ion diameter disrupt the double layer structure, promoting the adsorption of anions or inducing the density enhancement of small cations with diameters used in simulation studies of lithium solutions. The density enhancement of the small cations is mediated by their strong water solvation shell, with one or more water molecules "anchoring" the ion to the outermost water layer. We find that the intrinsic interfacial electrostatic potential features very strong oscillations with a minimum at the liquid surface that is ∼4 times stronger than the electrostatic potential in the bulk. For the water model employed in this work, SPC/E, the electrostatic potential at the water surface is ∼−2 V, equivalent to ∼80 k B T (for T = 300 K), much stronger than previously considered. Furthermore, we show that the utilization of the intrinsic surface technique provides a route to extract ionic potentials of mean force that are not affected by the thermal fluctuations, which limits the accuracy of most past approaches including the popular umbrella sampling technique.

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“…[41][42][43] Over the last decade, there have been important advances in the characterization of ξ (R) and its fluctuations, which can be done through the analysis of independent molecular configurations. [44][45][46][47][48][49][50][51][52] In this paper, we take advantage of these advances to quantify the fluctuation modes of biological membranes.…”

Section: A Instantaneous Shape ξ (R) Of the Membranementioning

confidence: 99%

Thermal fluctuations and bending rigidity of bilayer membranes

Tarazona

Chacón

Bresme

2013

The Journal of Chemical Physics

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We present a new scheme to estimate the elastic properties of biological membranes in computer simulations. The method analyzes the thermal fluctuations in terms of a coupled undulatory mode, which disentangle the mixing of the mesoscopic undulations and the high-q protrusions. This approach makes possible the accurate estimation of the bending modulus both for membranes under stress and in tensionless conditions; it also extends the applicability of the fluctuation analysis to the small membrane areas normally used in atomistic simulations. Also we clarify the difference between the surface tension imposed in simulations through a pressure coupling barostat, and the surface tension that can be extracted from the analysis of the low wave vector dependence of the coupled undulatory fluctuation spectrum. The physical analysis of the peristaltic mode is also refined, by separating the bulk and protrusions contributions. We illustrate the procedure by analyzing 1-palmitoyl-2-oleoylsn-glycero-3-phosphocholine and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine bilayers. The bending moduli obtained from our analysis, shows good agreement with available experiments. © 2013 AIP Publishing LLC. [http://dx

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Monte Carlo intrinsic surfaces and density profiles for liquid surfaces

Cited by 85 publications

References 39 publications

Mesoscopic Hamiltonian for the fluctuations of adsorbed Lennard-Jones liquid films

Mesoscopic Hamiltonian for the fluctuations of adsorbed Lennard-Jones liquid films

The structure of ionic aqueous solutions at interfaces: An intrinsic structure analysis

Thermal fluctuations and bending rigidity of bilayer membranes

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