Accelerating the dynamics of infrequent events

Conference · Wed Dec 31 04:00:00 EST 1997

OSTI ID:560433

Voter, A F ^[1]

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1. Los Alamos National Lab., NM (United States)

Molecular dynamics (MD) is a powerful tool for investigating detailed atomic-scale behavior on time scales of a nanosecond or less. For slower, infrequent-event processes, transition state theory (TST) can be employed, provided the nature of the transition states are known - i.e., if the relevant saddle points can be found. However, in many cases, the reactive events that will occur are not known in advance, or the transition states are very complicated. I discuss a new method for treating this type of case for solid-state systems. A bias potential, constructed from the gradient and Hessian, raises the energy of the system without affecting the TST dividing surfaces. Performing MD on the biased potential leads to accelerated transitions from state to state. In this {open_quotes}hyper-MD{close_quotes} approach, time is no longer an independent variable; the elapsed time is estimated as the simulation proceeds, converging on the correct time in the long-time limit. Hyper-MD simulations of metallic surface diffusion on the microsecond time scale will be presented.

• OSTI ID: 560433
• Report Number(s): CONF-970443--
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
CALCULATION METHODS
DIFFUSION
DYNAMICS
KINETICS
METALS