Correction of apparent finite size effects in the area per lipid of lipid membranes simulations.
Molecular dynamics simulations of lipids bilayers have reported that the average area per lipid increases with the size of the simulated unit cell under constant temperature, pressure, and number of molecules. Here we show that the cause of this finite size effect are artifacts associated with the heat bath coupling. This can be corrected by coupling individually each degree of freedom to the heat bath, instead of coupling globally the system. We present the results of the investigation on three aspects of molecular dynamics simulations and their effect on the computed average area per lipid: (I) the accuracy in the computation of electrostatic interactions, the energy, and the virial, (II) long range Lennard-Jones interactions for systems with symmetry in one plane, and (III) thermodynamic baths. We show that the average area per lipid remains constant for simulations of systems containing 32, 64, and 256 lipids.
Herce
Henry D
HD
Department of Physics, Rensselaer Polytechnic Institute, Troy, New York 12180, USA.
Garcia
Angel E
AE
D016477:Artifacts; D003198:Computer Simulation; D008051:Lipid Bilayers / Q000737:chemistry*; D008560:Membrane Fluidity; D008956:Models, Chemical; D008958:Models, Molecular; D010316:Particle Size
D008051:Lipid Bilayers