Molecular Dynamics for Polymeric Fluids Using Discontinuous Potentials

Abstract

Molecular dynamics simulation techniques for systems interacting with discontinuous potentials are discussed. Optimization and efficiency techniques are summarized for performing discontinuous molecular dynamics on serial computers with direct application to polymer-like fluids. Comparisons are presented for two algorithms: (1) single-event scheduling, and (2) multiple-event scheduling. The single-event scheduling algorithm is approximately 75% faster than the multiple-event scheduling algorithm for molecular fluids but yields equivalent performance for atomic fluids. For the single-event scheduling method, a combination of link lists and neighbor lists are used when searching for possible particle interactions. The combination of efficiency techniques permits multibillion time step simulations for relatively large systems on desktop workstations. Both discontinuous molecular dynamics codes for single and multiple-event scheduling algorithms are available on the Internet. The utility of the method is demonstrated for entangled chains, tethered chains, and heteronuclear chain mixtures.