INVESTIGADORES
DEL POPOLO Mario Gabriel
artículos
Título:
On the structure and dynamics of ionic liquids
Autor/es:
DEL POPOLO M.G., VOTH G.A.
Revista:
JOURNAL OF PHYSICAL CHEMISTRY B - (Print)
Editorial:
AMER CHEMICAL SOC
Referencias:
Año: 2004 vol. 108 p. 1744 - 1752
ISSN:
1520-6106
Resumen:
The structure and dynamics of the ionic liquid
1-ethyl-3-methylimidazolium nitrate is studied by molecular dynamics
simulations. We find long-range spatial correlations between the ions
and a three-dimensional local structure that reflects the asymmetry of
the cations. The main contribution to the configurational energy comes
from the electrostatic interactions which leads to charge-ordering
effects. Radial screening and three-dimensional distribution of charge
are also analyzed. The motion of a single ion is studied via velocity
and reorientational correlation functions. It is found that ions
rattle in a long-lived cage, while the orientational structure relaxes
on a time scale longer than 200 ps. As in a supercooled liquid, the
mean square displacements reveal a subdiffusive dynamics. In addition,
the presence of dynamic heterogeneities can be detected by analyzing the
non-Gaussian behavior of the van Hove correlation function and the
spatial arrangement of the most mobile ions. The short-time collective
dynamics is also studied through the electric current time correlation
function.