Large Dynamics of molten CF3SO3H·H2O probed by
temperature dependent dielectric spectroscopy
J. Barthel, R. Buchner, C.G.
Hölzl and B.E. Conway
J. Chem. Soc. Faraday Trans., 94 (1998) 1953-1958
Abstract
The complex permittivity spectra of CF3SO3H·H2O was
investigated in the frequency range 0.3-89 GHz at temperatures
from 298 to 338 K. The microwave spectra which show a very broad
absorption are analysed in terms of four Debye processes with relaxation
times t1 > t2
> t3 > t4.
Whereas t2, t3 and t4 exhibit Arrhenius behaviour at all temperatures, the
relaxation time of the slowest process, t1, exhibits an unusual
temperature dependence which can be fitted by assuming two Arrhenius
equations intersecting at approximately 315 K. At T >= 315 K the
t2 process is assigned to rotation of a mixture of the free acid
and its anion. The relaxation time t3 arises from the
reorientation of H2O or H3O+. For both relaxation processes
hydrodynamic boundary conditions are clos to slip. For the
high-frequency process, t4, the comparison with results from
MOPAC calculations suggests intramolecular rotation of the OH-group as
the dominating contribution.
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(c) 1998 Herbert Poepke
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