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Code:
ThP20
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Time Slot/Poster Number:
037
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Session:
Higher-order Raman (Fifth-order Raman/hyper Raman)
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Hyper-Raman scattering: a powerful tool to probe the structure in glasses
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| Guilhem Simon1; Bernard Hehlen2; René Vacher2; Eric courtens2
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1Université Pierre et Marie Curie, Paris VI, Thiais, France; 2Université Montpellier II, LCVN, Montpellier, France
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| View Abstract PDF |
| Summary |
The Hyper-Raman spectroscopy of various silicate and borate glasses has been performed. The selection rule analysis is based on a simple structural model considering a randomly connected network of well defined elementary structural units (ESUs). In silica the ESUs are the SiO4 tetrahedra while in borate glasses those are the BO3 triangles, the B3O3 rings, and the BO4 tetrahedra. The results show that the main HRS spectral components can be assigned to internal vibrations of ESUs, except for the boson peak which is associated to –quasi local- librations of rigid structural units, that is external-like motions.
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Code:
ThP20
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Time Slot/Poster Number:
038
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Session:
Higher-order Raman (Fifth-order Raman/hyper Raman)
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Two Dimensional Femtosecond Stimulated Raman Spectroscopy
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| Kristina Wilson; Randy Mehlenbacher; Brendon Lyons; David Mccamant
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University of Rochester, Rochester, NY
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| View Abstract PDF |
| Summary |
We will discuss a new methodology for two-dimensional Raman spectroscopy, termed two-dimensional femtosecond stimulated Raman spectroscopy (2D-FSRS). 2D-FSRS can potentially observe molecular anharmonicity by measuring the modulation of the frequency of a probed Raman mode by the coherent motion of an impulsively driven mode. However, as in other 2D-Raman techniques, the intended 5th-order Raman signal is easily overwhelmed by a third-order cascade. Our initial 2D spectra in acetonitrile and chroroform indicated that the third-order cascade dominated the signal. A novel classical theory of the 2D-FSRS can be combined with new experimental phase-matching techniques to isolate the 5th-order signal.
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Code:
ThP20
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Time Slot/Poster Number:
039
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Session:
Higher-order Raman (Fifth-order Raman/hyper Raman)
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Simultaneous Raman and Hyper-Raman Microspectroscopic Imaging
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| Korenobu Matsuzaki1; Rintaro Shimada1; Hiro-o Hamaguchi1, 2
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1The University of Tokyo, Tokyo, Japan; 2National Chiao Tung University, Hsinchu, Taiwan
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| View Abstract PDF |
| Summary |
Raman microspectroscopic imaging is a powerful tool to identify chemical
composition and its distribution based on vibrational spectroscopy. However, Raman microspectroscopy alone is sometimes insufficient, because of the limitations due to the selection rule and the spatial resolution constrained by the diffraction limit. These difficulties could be overcome by incorporating hyper-Raman microspectroscopy with
Raman microspectroscopy. In the present study, an experimental setup for simultaneous acquisition of Raman and hyper-Raman images is developed, and the obtained images of all-trans-beta-carotene microcrystals are examined.
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