?Thought-experiments? by molecular dynamics

Ciccotti, Giovanni; Jacucci, Gianni; McDonald, Ian R.

doi:10.1007/bf01011477

Cited by 201 publications

(150 citation statements)

References 17 publications

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“…31,32 For the shear viscosity calculations, we have employed the nonequilibrium periodic perturbation method. 33 The method was described in detail by Hess, 34 so we will limit ourselves to a brief outline. We perform a simulation in the NVT ensemble but add a periodic acceleration in the x direction, which is a where L z is the length of the box in the z direction, and the amplitude A is a tunable parameter.…”

Section: Potentials and Methodsmentioning

confidence: 99%

Molecular Dynamics Study of 2-Nitrophenyl Octyl Ether and Nitrobenzene

et al. 2006

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The pure organic liquids nitrobenzene (NB) and 2-nitrophenyl octyl ether (NPOE) have been studied by means of molecular dynamics simulations. Both solvents are extremely important in various interfacial processes, mainly connected with ion transfer taking place across the interface with water. Thermodynamic (mass density, enthalpy of vaporization, isothermal compressibility, dipole moment) and dynamic (viscosities and self-diffusion coefficients) properties of both liquids have been calculated and are in very good agreement with the experimental data. In the case of NB, several potentials have been tested and the obtained results compared and discussed. In most cases, the OPLS all-atom potential gives results that are in better agreement with available experimental values. Atomic radial distribution functions, dihedral and angle distributions, as well as dipole-orientation correlation functions are used to probe the structure and interactions of the bulk molecules of both organic solvents. These were seen to be very similar in terms of structure and thermodynamics, but quite distinct in terms of dynamic behavior, with NPOE showing a much slower dynamic response than NB. A simulation study of the simple Cl -and K + ions dissolved in both solvents has been also undertaken, revealing details about the diffusion and solvation mechanisms of these ions. It was found that in both liquids the positive potassium ion is solvated by the negative end of the molecular dipole, whereas the negative chloride ion is solvated by the positive end of the dipole.

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Section: Potentials and Methodsmentioning

confidence: 99%

Molecular Dynamics Study of 2-Nitrophenyl Octyl Ether and Nitrobenzene

et al. 2006

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“…The properties of the nonequilibrium steady state or the decay to the equilibrated state are then related to the viscosity. One example is a periodic perturbation employed to generate an oscillatory velocity profile, 9 depending on the frequency of the sinusoidal external force. Several measurements at different frequencies and extrapolation to zerofrequency are required to determine the viscosity.…”

Section: Introductionmentioning

confidence: 99%

Poiseuille flow to measure the viscosity of particle model fluids

Backer

Lowe

Hoefsloot

et al. 2005

The Journal of Chemical Physics

195

156

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Poiseuille flow to measure the viscosity of particle model fluids.Backer, J.A.; Lowe, C.P.; Hoefsloot, H.C.J.; Iedema, P.D. General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. The most important property of a fluid is its viscosity, it determines the flow properties. If one simulates a fluid using a particle model, calculating the viscosity accurately is difficult because it is a collective property. In this article we describe a new method that has a better signal to noise ratio than existing methods. It is based on using periodic boundary conditions to simulate counter-flowing Poiseuille flows without the use of explicit boundaries. The viscosity is then related to the mean flow velocity of the two flows. We apply the method to two quite different systems. First, a simple generic fluid model, dissipative particle dynamics, for which accurate values of the viscosity are needed to characterize the model fluid. Second, the more realistic Lennard-Jones fluid. In both cases the values we calculated are consistent with previous work but, for a given simulation time, they are more accurate than those obtained with other methods.

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“…giving a negative interaction biaxility, produces particles with a dual nature: rod-like from the point of view of shape, and disc-like with respect to interactions [13] (see Figure 7). Virtual MD experiments [124] have been used to estimate the switching times of the principal and secondary director of this model N b [125]. The reorientation of the secondary director m has been found to be, on average, an order of magnitude faster than that of n. This kind of direct measurement of a response might be useful for screening the technological suitability of N b phases in displays and other devices since in virtual experiment the setup such as sample shape, pair potential, anchoring geometry and strength, and coupling to an external field can be controlled by design without a prior knowledge of mesoscopic response coefficients.…”

Section: Single-site Modelsmentioning

confidence: 99%