System size dependence and time convergence in molecular dynamics simulations of monolayer films

The sample size dependence and time convergence of property values of simple hydrocarbon monolayers has been investigated by performing molecular dynamics simulations at four surface coverages for systems ranging in size from 16 to 100 chains and for trajectories as long as 200 ps. Detailed studies of the tilt angle indicate that systems with 64 chains simulated for 40 ps (in addition to a 40 ps equilibration stage) are large enough to obtain statistically meaningful results. The equilibrium tilt angle is slightly sensitive to the boundary conditions.