Dynamical correlations in simple disorder and complex disorder liquids
Résumé
Liquids in equilibrium exhibit two types of disorder, simple and com-
plex. Typical simple disorder liquid are liquid nitrogen, or weakly polar
liquids. Complex liquids concern those who can form long lived local as-
semblies, and cover a large range from water to some soft matter and bio-
logical liquids. The existence of such structures leaves characteric features
upon the atom-atom correlation functions, concerning both atoms which
directly participate to these structure and those who do not. The ques-
tion we ask here is: do these features have also characteristic dynamical
aspects, which could be tracked through dynamical correlation functions?
Herein, we compare the van Hove function, intermediate scattering func-
tion and the dynamical structure factor, for both types of liquids, using
force eld models and computer simulations. The calculations reveal the
paradoxical fact that neighbouring atom correlations for simple disorder
liquids relax slower than that for complex disorder liquids, while prepeak
features typical of complex disorder liquids relax even slower. This is an
indication of the existence of fast kinetic self-assembly processes in com-
plex disorder liquids, while the lifetime of such assemblies itself is quite
slow. This is further conrmed by the existence of a very low-k dynamical
pre-peak uncovered in the case of water and ethanol.
Domaines
Chimie théorique et/ou physiqueOrigine | Fichiers produits par l'(les) auteur(s) |
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