(369n) A Control Strategy for Thermostating and Barostating Molecular Dynamics Simulations

In molecular dynamics (MD) simulations, temperature control (thermostating) plays an important role in the canonical ensemble (NVT ensemble) calculation. In the past, numerous thermostating algorithms were published [1-4]. The Nosé-Hoover thermostat [4] is one of well-known conventional methods, which integrates error terms over time. Inspired by the Nosé-Hoover thermostat, a PID-like control strategy is proposed and used for MD simulations with the NVT ensemble. The proposed algorithm provides flexibility in MD thermostating. MD simulation results show that the equilibrium time becomes shorter, while overshoots and fluctuations are less pronounced than in the Nosé-Hoover thermostat. The concept has also been extended to pressure control (barostating). We are currently interfacing the proposed algorithm to the well-known open-source MD code, LAMMPS for simulation of complex systems. We are also constructing MPC-like control. 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 proposed algorithm continues to be explored.

References:

[1] Berendsen, H. J., Postma, J. V., van Gunsteren, W. F., DiNola, A. R. H. J., & Haak, J. R. (1984). Molecular dynamics with coupling to an external bath. The Journal of chemical physics, 81(8), 3684-3690.

[2] Andersen, H. C. (1980). Molecular dynamics simulations at constant pressure and/or temperature. The Journal of chemical physics, 72(4), 2384-2393.

[3] Nosé, S. (1984). A unified formulation of the constant temperature molecular dynamics methods. The Journal of chemical physics, 81(1), 511-519.

[4] Hoover, W. G. (1985). Canonical dynamics: equilibrium phase-space distributions. Physical review A, 31(3), 1695.