Decoupling phenomena in supercooled liquids: signatures in the energy landscape.

Metastable states as a key to the dynamics of supercooled liquids

Computer simulations of a model glass-forming system are presented, which study the correlation between the dynamics in real space and the topography of the potential energy landscape. This analysis clearly reveals that in the supercooled regime the dynamics is strongly influenced by the presence of deep valleys in the energy landscape, corresponding to long-lived metastable amorphous states. W...

Theory of Supercooled Liquids and Glasses: Energy Landscape and Statistical Geometry Perspectives

Saddles in the energy landscape probed by supercooled liquids.

We numerically investigate the supercooled dynamics of two simple model liquids exploiting the partition of the multidimensional configuration space in basins of attraction of the stationary points (inherent saddles) of the potential energy surface. We find that the inherent saddle order and potential energy are well-defined functions of the temperature T. Moreover, by decreasing T, the saddle ...

Relationship between fragility, diffusive directions and energy barriers in a supercooled liquid

An analysis of diffusion in a supercooled liquid based solely in the density of diffusive directions and the value of energy barriers shows how the potential energy landscape (PEL) approach is capable of explaining the a and b relaxations and the fragility of a glassy system. We find that the b relaxation is directly related to the search for diffusive directions. Our analysis shows how in stro...

Coherent neutron scattering and collective dynamics on mesoscale.

By combining, and modestly extending, a variety of theoretical concepts for the dynamics of liquids in the supercooled regime, we formulate a simple analytic model for the temperature and wavevector dependent collective density fluctuation relaxation time that is measurable using coherent dynamic neutron scattering. Comparison with experiments on the ionic glass-forming liquid Ca-K-NO3 in the l...