Picosecond time-resolved Raman

When an electron is injected into a polar solvent such as water or alcohols, the electron is solvated and forms so-called the solvated electron. This solvated electron is considered the most basic anionic species in solutions and it has been extensively studied by variety of experimental and theoretical methods. Especially, the solvated electron in water (the hydrated electron) has been attracting much interest in wide fields because of its fundamental importance. It is well-known that the solvated electron in water exhibits a very broad absorption band peaked around 720 nm. This broad absorption is mainly attributed to the s- p transition of the electron in a solvent cavity. Recently, we measured picosecond time-resolved Raman scattering from water under the resonance condition with the s- p transition of the solvated electron, and found that strong transient Raman bands appeared in accordance with the generation of the solvated electron [1]. It was concluded that the observed transient Raman scattering was due to the water molecules that directly interact with the electron in the first solvation shell. Similar results were also obtained by a nanosecond Raman study [2]. This finding implies that we are now able to study the solvated electron by using vibrational spectroscopy. In this paper, we describe new information about the ultrafast dynamics of the solvated electron in water, which are obtained by time-resolved resonance Raman spectroscopy. 

The first subsurface bone tissue Raman spectroscopic measurements were performed using picosecond time-resolved Raman spectroscopy on excised equine cortical bone [56, 57], In these experiments it was shown that a polystyrene backing could be detected through 0.3 mm of bone. The same picosecond technology was used to perform the first transcutaneous Raman spectroscopic measurements of bone tissue [58]. In this study, the cortical bone mineral/matrix ratios of excised limbs of wild type and transgenic (oim/oim) mice were compared and the differences demonstrated. 

Aramaki et al.30 examined the photochromic reactions of spirooxazines by picosecond time-resolved Raman spectroscopy. Vibrational resonance Raman spectra of the merocyanine isomer(s) recorded over a 50-ps-1.5-ns interval did not change. This indicated that the open ring opening to form a stable merocyanine isomer or the distribution of isomers31 was complete within 50 ps and that the isomer(s) distribution remained unchanged for at least 1.5 ns. 

S. Aramaki and G. H. Atkinson, Spirooxazine photochromism picosecond time-resolved Raman and absorption spectroscopy, Chem. Phys. Lett., 170, 181-186 (1990). 

Vibrational Cooling Process in Solution Probed by Picosecond Time-Resolved Raman Spectroscopy. Analysis of the Cooling Kinetics. 

The time-resolved Raman spectra were measured with a picosecond time-resolved Raman spectrometer which employs a standard pump-probe technique. The details of the spectrometer have been publish elsewhere. The followings are concise description of the apparatus The output from a synchronously pumped mode-locked dye laser is amplified with the output from a cw Nd YAG regenerative amplifier. The second harmonic (294 nm, 2 kHz, 1-2 mW) of the amplified light (588 nm, 3.2 ps, 2 kHz, 15 mW) was used as a... 

Fujino, T., and Tahara, T. (2000). Picosecond time-resolved Raman study of trans-azobenzene./. Phys. Chem. A, 104, 4203-4210. 

Iwata, K. and Hamaguchi, H. (1994) Picosecond time-resolved Raman-spectroscopy of SI p-terphenyl and p-terphenyl-d]4 in solution - time-dependent changes of Raman band shapes. J. Raman Spectrosc., 25,... 

Picosecond time-resolved Raman studies have been used... 

In picosecond time-resolved Raman spectroscopy, the sample is pumped and probed by energetically well-defined optical pulses, producing a full vibrational spectrum over a 1000 2000 cm 1 window.207 One would expect vibrational spectroscopy to be restricted to the picosecond time domain and above by the Heisenberg uncertainty principle (Equation 2.1), because a 1 ps transform-limited pulse has an energy width of... 

Iwata, K. Hamaguchi, H.-O., Microscopic mechanism of solute-solvent energy dissipation probed by picosecond time-resolved Raman spectroscopy. J. Phys. Chem. A 1997, 101, 632-637. 

Fujino T, Tahara T. 2000. Picosecond time resolved raman study of trans azobenzene. J Phys Chem A 104(18) 4203 4210. 

Picosecond time-resolved Raman spectroscopy has been used to study the ultrafast relaxation dynamics of trows-stilbene cation radicals following two-photon ionization in acetonitrile [66]. The integrated Raman intensities due to the cation radicals rise in... 

Time-resolved anti-Stokes Raman spectroscopy was used for monitoring vibrational relaxation dynamics in solution and provides information about specific modes in molecules under investigation [58, 59]. The experimental setup of a picosecond time-resolved Raman spectrometer is schematically shown in Figure 11.15 [59]. Probe-wavelength dependence of picosecond time-resolved anti-Stokes Raman spectra of a molecule under study allowed determination of... 

Vibrational cooling rates in room temperature ionic liquids were measured with picosecond time-resolved Raman spectroscopy [63]. The 1570-cm Raman band of the first excited singlet (Sj) state of frans-stilbene was used. The recorded vibrational cooling rates in l-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (emimTf2N) and l-butyl-3-methylimidazolium bis(trifluoromethylsu]fonyl)imide (bmimTf2N) were close to those in ordinary molecular solvents despite a large difference in thermal diffusivity. 

Iwata, K., Yoshida, K., Takada, Y. and Hamaguchi, H., Vibrational cooling process of trans-stilbene in ionic liquids observed with picosecond time-resolved Raman spectroscopy, Chem. Lett. 36, 504-505 (2007). 

Everall N, Hahn T, Matuosek P, Parker A, Towrie M (2001) Picosecond time-resolved Raman spectroscopy of solids capabilities and limitations for fluorescence rejection and the influence of diffuse reflectance. Appl Spectrosc 55 1701-1708 Gaft M, Nagli L (2008) Laser-based spectroscopy for standoff detection of explosives. Opt Mater... 

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