Constant-pressure and constant-surface tension simulations in dissipative particle dynamics

Abstract

We present a method for constant-pressure and constant-surface tension simulations in dissipative particle dynamics using a Langevin piston approach. We demonstrate that the corresponding equations of motion lead to the relevant ensembles and propose an appropriate scheme of integration. After having identified a suitable set of parameters for the approach, we demonstrate the feasibility of the approach by applying it to two different systems, a simple isotropic fluid and an anisotropic fluid lipid-bilayer membrane in water. Results are presented for, respectively, isothermal bulk compressibility, tracer diffusion coefficient, lipid head-group area, and isothermal area compressibility. We find that our Langevin piston approach leads to improvements over other approaches in terms of faster equilibration and shorter correlation times of various system variables.

Dissipative particle dynamics at isothermal, isobaric, isoenergetic, and isoenthalpic conditions using Shardlow-like splitting algorithms

“…either a Hoover or Langevin barostat. 13 DPD-P allows control over both the temperature and the pressure, where in typical fashion, the cell volume fluctuates to satisfy the imposed pressure. An extension not currently available within the DPD framework is an approach that imposes constant-enthalpy conditions (DPD-H).…”

Biological and synthetic membranes: What can be learned from a coarse-grained description?

“…This longer-ranged attraction, which acts only between the interface beads, is sufficient to stabilize fluid bilayer membranes at reduced temperature, k B T /ǫ = 0.9. A different path to the development of generic coarse-grained models has been pursued by Groot [ 184,185], Smit [ 186,187,188,189,190,191], Shillcock [ 142,192,193,194] and Mouritsen [ 195,196] with their co-workers. These coarse-grained models utilize ultra-soft interactions in conjunction with a dissipative particle dynamics (DPD) thermostat [ 197,198,199,200,201].…”

Communications: Self-energy and corresponding virial contribution of electrostatic interactions in dissipative particle dynamics: Simulations of cationic lipid bilayers

“…To simulate bilayers at any constant surface tension, NP Ќ ␥ s T ͑P Ќ is the normal pressure͒ ensemble should be used. 17 At ␥ s = 0, it reduces to NPT ensemble.…”

“…2 In NPT ensemble, Langevin piston approach is employed. 16,17 Initially, a bilayer slab composed of 1600 lipids are placed on the x-y plan in the center of a orthogonal box with size 32r 0 ϫ 32r 0 ϫ 32r 0 . CL counterions and water are randomly distributed in the space unoccupied by the slab.…”