Accelerated molecular dynamics simulation of low-velocity frictional sliding

Accelerated molecular dynamics (MD) simulations are implemented to model the sliding process of atomic force microscope (AFM) experiments and to lower the sliding speeds below those in a conventional MD simulation. In this study the hyperdynamics method, originally devised to extend MD time scales for non-driven systems, is applied to the frictional sliding system. This technique is combined with a parallel algorithm that simultaneously simulates the system over a range of slider positions so that the overall acceleration rate is approximately the number of processors multiplied by the boost factor from the hyperdynamics method. The new methodologies are tested using two-dimensional and three-dimensional Lennard-Jones AFM models. Direct comparison with the results from conventional MD shows close agreement validating the methods. The acceleration rate achieved in this study is four orders of magnitude in 2D and three orders of magnitude in 3D.