Res. Chem. Intermed.
, Vol. 31, No. 7–8, pp. 703–716 (2005)
Also available online - www.vsppub.com
Vibrational dynamics in liquids studied by non-linear
, KAORU OHTA
and KEISUKE TOMINAGA
Graduate School of Science and Technology, Kobe University, Nada, Kobe 657-8501, Japan
Molecular Photoscience Research Center, Kobe University, Nada, Kobe 657-8501, Japan
CREST/JST, Kawaguchi Center Building, 4-1-8, Honcho, Kawaguchi-shi,
Saitama 332-0012, Japan
Received 16 March 2004; accepted 8 June 2004
Abstract—Three-pulse photon echo experiments in the infrared region have been performed to
study vibrational dephasing and transition frequency ﬂuctuations in solutions. Time-integrated and
frequency-resolved photon echo signals of the
N C N anti-symmetric stretching mode of di-
p-tolylcarbodiimide show an oscillatory behavior due to interference with a band nearby. Solvation
dynamics or frequency ﬂuctuations of several ions in hydrogen-bonding solvents have been studied
and a couple of general trends of the time-correlation function of the frequency ﬂuctuation on these
systems have been observed.
Keywords: Three-pulse photon echo; vibrational dephasing; solvation dynamics; di-p-tolylcarbo-
diimide; non-linear infrared spectroscopy.
Molecular dynamics in liquids are strongly affected by intermolecular interactions.
It is of great importance to obtain a molecular description of the relationship be-
tween the dynamics and interactions in liquids in order to elucidate the solvent
dynamic effect on chemical reactions. Fluctuations of the vibrational transition
energies, which are characterized by time-correlation functions of the frequency
ﬂuctuations, are very sensitive to dynamics of surrounding environments. There-
fore, the microscopic view on liquid dynamics by probing the vibrational ﬂuctua-
tions has been investigated. Recent progress of laser technology to generate short
pulses with a high energy in the infrared region has enabled us to perform non-
linear spectroscopy on vibrational modes in solutions to study dynamical aspects of
the vibrational transitions [1 –9].
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