Rotational dynamics in a simulated supercooled network-forming liquid

We discuss the coupling between rotational and translational motions in a simulated network forming liquid, i.e. the extended simple point charge (SPC/E) model developed to describe the behavior of water, a network of hydrogen bonds. We show that rotational correlators in supercooled states behave as predicted by mode-coupling theory (MCT) and present a simple modification of the standard MCT to describe the wave vector and time dependence of the center of mass (COM) correlators. We compare the predictions of the model with the numerical data, calculated from a molecular dynamics (MD) simulation. (C) 1998 Elsevier Science B.V. All rights reserved.