54,1-order Raman signal liquid

A large amount of effort has been devoted to evaluating the fifth-order Raman signal for a variety of systems. The first method used in such simulations is the multi-mode Brownian oscillator (MMBO) model [16] which approached the problem as a system of oscillators coupled to a heat bath. The oscillators are obtained from a fit of the low-frequency spectrum of the liquid in question ... 

Fig. 1.7 Fifth-order Raman signal intensity for liquid Xe calculated using INM. Note the distinct echo signal along the time diagonal (fi =t2) [42]. Reused with permission from [42], Copyright 2002, American Institute of Physics...

Fig. 2. Fleterodyne detected fifth-order Raman response of liquid CS2 for two different polarization conditions (A) Rnnn and (B, C) the Dutch Cross , Rl-liill, configuration. The solid curves are the in-phase signals, and the dashed lines are the 7t/2 shifted signals (not discussed). Panels B, and C show slices along Z and the diagonal. L = 60°...

The buried nature of the liquid/liquid junctions introduces tremendous difficulties for in-situ spectroscopic analysis of species confined to the interfacial region. UV-visible absorption, luminescence, and Raman signal associated with species at the interface are overwhelmed by the signal arising from the species in the bulk liquids. In this section, different approaches are highlighted in order to increase the linear optical signals arising from probes located at the interface. 

In its short infancy, fifth-order Raman spectroscopy has caused a remarkable shift in our theoretical and experimental understanding of liquids. Theories have been raised up and cast down and experiments have been exhaustively characterized and criticized all to ensure that we properly understand these low-frequency dynamics. In some sense, the fifth-order Raman response has served as a proving ground for both theory and experiment. The 2D fifth-order Raman experiment represents an extraordinary challenge to the experimentalist. The signal is inherently very small and new methodologies were required to be able to pull... 

The field of fifth-order Raman spectroscopy is still in its infancy. There are many experimental and theoretical challenges that lie ahead. The simple liquid CS2 has finally been resolved and there is preliminary evidence that this form of spectroscopy can be extended to other systems with signal having been... 

The fourth-order coherent Raman spectrum of a liquid surface was observed by Fujiyoshi et al. [28]. The same authors later reported a spectrum with an improved signal-to-noise ratio and different angle of incidence [27]. A water solution of oxazine 170 dye was placed in air and irradiated with light pulses. The SH generation at the oxazine solution was extensively studied by Steinhurst and Owrutsky [24]. The pump and probe wavelength was tuned at 630 nm to be resonant with the one-photon electronic transition of the dye. The probability of the Raman transition to generate the vibrational coherence is enhanced by the resonance. The efficiency of SH generation is also enhanced. 

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