CiteULike: 著者: Fichthorn

Theoretical foundations of dynamical Monte Carlo simulations

Kristen Fichthorn — 2008-05-10T02:13:22-00:00

The Journal of Chemical Physics, Vol. 95, No. 2. (1991), pp. 1090-1096.

Multiple-Time Scale Accelerated Molecular Dynamics: Addressing the Small-Barrier Problem

RA Miron — 2007-06-27T12:59:32-00:00

Physical Review Letters, Vol. 93, No. 12. (September 2004), 128301.

We present a method for accelerated molecular-dynamics simulation in systems with rare-event dynamics that span a wide range of time scales. Using a variant of hyperdynamics, we detect, on the fly, groups of recurrent states connected by small energy barriers and we modify the potential-energy surface locally to consolidate them into large, coarse states. In this way, fast motion between recurrent states is treated within an equilibrium formalism and dynamics can be simulated over the longer time scale of the slow events. We apply the method to simulate cluster diffusion and the initial growth of Co on Cu(001),where time scales spanning more than 6 orders of magnitude are present, and show that the method correctly follows the slow events, so that much larger times can be simulated than with accelerated molecular dynamics alone.

Accelerated molecular dynamics with the bond-boost method

RA Miron — 2007-06-27T10:15:42-00:00

J. Chem. Phys., Vol. 119 (September 2003), pp. 6210-6216.

We present a new method for accelerating molecular-dynamics simulations of infrequent events. The method targets simulation of systems that spend most of the time in local energy minima, with slow transitions in between, as is the case with low-temperature surface diffusion. The potential-energy surface is modified by adding a boost potential in regions close to the local minima, such that all transition rates are increased while relative rates are preserved. The boost potential is an empirical function determined by the deviation of the bond lengths of a specified set of atoms from equilibrium. The method requires no previous knowledge of the processes involved and it can be applied to a wide variety of interaction potentials. Application to the diffusion of Cu atoms on the Cu(100) surface using an embedded-atom potential yields correct rates for adatom hopping, exchange, as well as vacancy and dimer diffusion with speed-ups up to several orders of magnitude. © 2003 American Institute of Physics.