Ab initio molecular dynamics (AIMD) methods combine the efficient locality of classical MD with the accuracy of on-the-fly electronic structure theory potentials and forces. Accordingly, AIMD can uniquely treat challenging chemical dynamics, including instances of strong polarization, charge transfer, and the making and breaking of chemical bonds. The many-orders-of-magnitude cost increase over empirical potentials, however, limits the time and length scale of problems to which it can be applied. In this presentation, a series of new developments in AIMD is presented, all of which fall under the umbrella of multiple-timestep MD methods. These methods exploit the spatial and temporal separability inherent to common electronic structure theory methods, for the purpose of accelerated dynamics simulations. Such separability is not always obvious, and the presentation will explore the physical justification for these approaches. Many of the common "knobs" available in ab initio methods will be shown to be amenable to such techniques, and additional methods, which dig more deeply into the innards of electronic structure theory to address cost scaling, will also be presented. Finally, the dynamics of reactive chemical systems--for which ab initio potentials are especially necessary--will be presented as demonstrations of these methods.

Advancing ab initio molecular dynamics via multiple-timestep methods

249th National Meeting (2015)

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