Generalized Langevin equation for solids. II. Stochastic boundary conditions for nonequilibrium molecular dynamics simulations

Kantorovich, Lev; Rompotis, N.

doi:10.1103/physrevb.78.094305

Cited by 62 publications

(63 citation statements)

References 31 publications

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“…This technique is particularly useful for large, complex systems where the wall atoms can be "frozen" to preserve structural stability and reduce the computational cost [59]. Stochastic boundary conditions (SBC) [60], in which the border atoms experience random friction forces (Langevin) to control the flow of energy through the system border, have also been shown to be effective in temperature control of confined NEMD simulations of tribological systems [61].…”

Section: Temperature and Pressure Controlmentioning

confidence: 99%

Advances in nonequilibrium molecular dynamics simulations of lubricants and additives

2018

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Nonequilibrium molecular dynamics (NEMD) simulations have provided unique insights into the nanoscale behaviour of lubricants under shear. This review discusses the early history of NEMD and its progression from a tool to corroborate theories of the liquid state, to an instrument that can directly evaluate important fluid properties, towards a potential design tool in tribology. The key methodological advances which have allowed this evolution are also highlighted. This is followed by a summary of bulk and confined NEMD simulations of liquid lubricants and lubricant additives, as they have progressed from simple atomic fluids to ever more complex, realistic molecules. The future outlook of NEMD in tribology, including the inclusion of chemical reactivity for additives, and coupling to continuum methods for large systems, is also briefly discussed.

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Section: Temperature and Pressure Controlmentioning

confidence: 99%

Advances in nonequilibrium molecular dynamics simulations of lubricants and additives

2018

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“…Indeed, as was shown in Ref. [60], any value of the friction coefficient, even if applied not to all atoms of the system, would always bring the system to the equilibrium state described by the corresponding canonical distribution. Hence, the value of the friction parameter(s) can only be obtained by running genuinely nonequilibrium simulations, e.g., on heat transport, rate of equilibration, and so on.…”

Section: Summary and Discussionmentioning

confidence: 96%

Applications of the generalized Langevin equation: Towards a realistic description of the baths

et al. 2015

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The generalized Langevin equation (GLE) method, as developed previously [L. Stella et al., Phys. Rev. B 89, 134303 (2014)], is used to calculate the dissipative dynamics of systems described at the atomic level. The GLE scheme goes beyond the commonly used bilinear coupling between the central system and the bath, and permits us to have a realistic description of both the dissipative central system and its surrounding bath. We show how to obtain the vibrational properties of a realistic bath and how to convey such properties into an extended Langevin dynamics by the use of the mapping of the bath vibrational properties onto a set of auxiliary variables. Our calculations for a model of a Lennard-Jones solid show that our GLE scheme provides a stable dynamics, with the dissipative/relaxation processes properly described. The total kinetic energy of the central system always thermalizes toward the expected bath temperature, with appropriate fluctuation around the mean value. More importantly, we obtain a velocity distribution for the individual atoms in the central system which follows the expected canonical distribution at the corresponding temperature. This confirms that both our GLE scheme and our mapping procedure onto an extended Langevin dynamics provide the correct thermostat. We also examined the velocity autocorrelation functions and compare our results with more conventional Langevin dynamics.

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“…To study the thermal transport of 1D atomic chains, we used our recently developed GLE scheme 56,57 . The method and its implementation in the molecular dynamics package LAMMPS 58 have been well documented in recent papers 59,60 .…”

Section: Methods and Systemsmentioning

confidence: 99%

Nonequilibrium generalised Langevin equation for the calculation of heat transport properties in model 1D atomic chains coupled to two 3D thermal baths

Ness

Stella

Lorenz

et al. 2017

The Journal of Chemical Physics

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We use a Generalised Langevin Equation (GLE) scheme to study the thermal transport of low dimensional systems. In this approach, the central classical region is connected to two realistic thermal baths kept at two different temperatures [H. Ness et al., Phys. Rev. B 93, 174303 (2016)]. We consider model Al systems, i.e. onedimensional atomic chains connected to three-dimensional baths. The thermal transport properties are studied as a function of the chain length N and the temperature difference ∆T between the baths. We calculate the transport properties both in the linear response regime and in the non-linear regime. Two different laws are obtained for the linear conductance versus the length of the chains. For large temperatures (T 500 K) and temperature differences (∆T 500 K), the chains, with N > 18 atoms, present a diffusive transport regime with the presence of a temperature gradient across the system. For lower temperatures(T 500 K) and temperature differences (∆T 400 K), a regime similar to the ballistic regime is observed. Such a ballistic-like regime is also obtained for shorter chains (N ≤ 15). Our detailed analysis suggests that the behaviour at higher temperatures and temperature differences is mainly due to anharmonic effects within the long chains.

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Generalized Langevin equation for solids. II. Stochastic boundary conditions for nonequilibrium molecular dynamics simulations

Cited by 62 publications

References 31 publications

Advances in nonequilibrium molecular dynamics simulations of lubricants and additives

Advances in nonequilibrium molecular dynamics simulations of lubricants and additives

Applications of the generalized Langevin equation: Towards a realistic description of the baths

Nonequilibrium generalised Langevin equation for the calculation of heat transport properties in model 1D atomic chains coupled to two 3D thermal baths

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