Atomic Dynamics in Real Space and Time

Abstract

Atomic and molecular dynamics in strongly disordered matter, such as liquid, cannot be fully described in terms of phonons, because they are marginalized and often overdamped. Their dynamic and transport properties depend on local atomic rearrangements which are strongly correlated. To describe such local dynamics, the usual representation in momentum (Q) and energy (E) space in terms of the dynamic structure factor, S(Q, E), is not effective. We discuss an alternative approach in real space (r) and time (t), with the van Hove function, G(r, t), and show how this approach facilitates understanding of real-space local dynamics of liquids and other disordered systems in the length scale of Å and time scale of pico-second.