(189bw) PID Control Strategy for Thermostating and Barostating Molecular Dynamics Simulation

In molecular dynamics (MD) simulations, a number of temperature control methods (thermostating) have been employed for decades [1-4]. A well-known conventional method is the Nosé-Hoover thermostat [4], which acts like an integral control method. Within process systems engineering, the proportional-integral-derivative control (PID) is well established for decentralized single control loops. In this research, the authors have developed a PID framework (PIDStat) for MD thermostating. The PID formalism allows flexibility in MD thermostating. In NVT ensembles it is observed that through the suggested approach, the equilibrium time becomes shorter, while overshoots and fluctuations are less pronounced than in the Nosé-Hoover thermostat. PIDStat has been extended to pressure control (barostating). The authors are currently interfacing PIDStat to the well-known open-source MD code, LAMMPS for simulation of complex systems. The expectation is that thermostating and barostating can be accomplished within a shorter period of time, thus allowing for tackling larger problems. The advantages of PIDStat continues to be explored.