TY - JOUR
T1 - Rattling the cage: Micro- to mesoscopic structure in liquids as simple as argon and as complicated as water
AU - Turton, David A.
AU - Hunger, Johannes
AU - Stoppa, Alexander
AU - Thoman, Andreas
AU - Candelaresi, Marco
AU - Hefter, Glenn
AU - Walther, Markus
AU - Buchner, Richard
AU - Wynne, Klaas
N1 - Anuual Meeting of the European Molecular Liquid Group/Japanese Molecular Liquid Group, Salzburg, AUSTRIA, SEP 06-10, 2009
PY - 2011/2/15
Y1 - 2011/2/15
N2 - The water molecule has the convenient property that its molecular polarizability tensor is nearly isotropic while its dipole moment is large. As a result, the low-frequency anisotropic Raman spectrum of liquid water is mostly collision-induced and therefore reports primarily translational motions while the far-infrared (terahertz) and dielectric spectrum is dominated by rotational modes. Atomic and globular-molecular liquids have a zero dipole moment as well as an isotropic polarizability tensor. These spectrum-simplifying properties were exploited in a study of a number of liquids and solutions using ultrafast optical Kerr-effect COKE) spectroscopy combined with dielectric relaxation spectroscopy (DRS), terahertz time-domain spectroscopy (THz-TDS), and terahertz field-induced second-harmonic generation (TFISH) spectroscopy. For room-temperature ionic liquids (RTILs), liquid water, aqueous salt solutions, noble gas liquids, and globular-molecular liquids it was found that, in each case, surprising structure and/or inhomogeneity is observed, ranging from mesoscopic clustering in RTILs to stretched-exponential dynamics in the noble gas liquids. For aqueous electrolyte solutions it is shown that the viscosity, normally described by the Jones-Dole expression, can be explained in terms of a jamming transition, a concept borrowed from soft condensed matter studies of glass transitions in colloidal suspensions. (C) 2010 Elsevier B.V. All rights reserved.
AB - The water molecule has the convenient property that its molecular polarizability tensor is nearly isotropic while its dipole moment is large. As a result, the low-frequency anisotropic Raman spectrum of liquid water is mostly collision-induced and therefore reports primarily translational motions while the far-infrared (terahertz) and dielectric spectrum is dominated by rotational modes. Atomic and globular-molecular liquids have a zero dipole moment as well as an isotropic polarizability tensor. These spectrum-simplifying properties were exploited in a study of a number of liquids and solutions using ultrafast optical Kerr-effect COKE) spectroscopy combined with dielectric relaxation spectroscopy (DRS), terahertz time-domain spectroscopy (THz-TDS), and terahertz field-induced second-harmonic generation (TFISH) spectroscopy. For room-temperature ionic liquids (RTILs), liquid water, aqueous salt solutions, noble gas liquids, and globular-molecular liquids it was found that, in each case, surprising structure and/or inhomogeneity is observed, ranging from mesoscopic clustering in RTILs to stretched-exponential dynamics in the noble gas liquids. For aqueous electrolyte solutions it is shown that the viscosity, normally described by the Jones-Dole expression, can be explained in terms of a jamming transition, a concept borrowed from soft condensed matter studies of glass transitions in colloidal suspensions. (C) 2010 Elsevier B.V. All rights reserved.
KW - mesoscopic
KW - noble gas liquids
KW - electrolyte
KW - water
KW - room-temperature ionic liquids
KW - nanoscale
KW - jamming
KW - fischer clusters
UR - http://www.scopus.com/inward/record.url?scp=79952003046&partnerID=8YFLogxK
U2 - 10.1016/j.molliq.2010.04.005
DO - 10.1016/j.molliq.2010.04.005
M3 - Article
SN - 0167-7322
VL - 159
SP - 2
EP - 8
JO - Journal of Molecular Liquids
JF - Journal of Molecular Liquids
IS - 1
ER -