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Center for Nonlinear Studies |
Many important materials processes take place on time scales that greatly exceed the roughly one microsecond accessible to molecular dynamics simulation. Typically, this long-time dynamical evolution is characterized by a succession of thermally activated infrequent events involving defects in the material. Since the late 1990's, we have been developing a class of methods, accelerated molecular dynamics, in which the known characteristics of infrequent-event systems are exploited to make reactive events take place more frequently, in a dynamically correct way. For certain processes, this approach has been remarkably successful, offering a view of complex dynamical evolution on time scales of microseconds, milliseconds, and sometimes beyond. Examples include metallic surface diffusion and growth, radiation damage annealing, and dynamics of nanotubes and nanoscale clusters. In this lecture, I will give an introduction to infreqent events in materials and to these accelerated molecular dynamics (AMD) methods: hyperdynamics, parallel-replica dynamics and temperature accelerated dynamics, along with some application examples. Time permitting, I will then briefly discuss some recent developments designed to make the AMD methods more general, more efficient, more scalable for large systems, and more capable of exploiting massively parallel environments.
Host: Amanda Neukirch