Slow dynamics in glass-forming materials

Dynamical properties of glass-formers such as glassy crystals, molecular liquids and model atomic liquids have been investigated in the pico-nanosecond (ps-ns) regime with dl_poly. The change in nature of translation and rotational dynamics are investigated in the supercooled state. Some predictions of the mode-coupling theory and the coupling model are checked. The microscopic origin of the fragility, i.e. the characteristic parameter involved in the liquid-glass transition, is also highlighted: the interaction potential, especially its anharmonicity and capacity for intermolecular coupling, is the key parameter controlling both the long time dynamics in supercooled systems and the short time dynamics in their glassy states.