Crystal Raman scattering

Chang T-C and DIott D D 1988 Picosecond vibrational cooling in mixed molecular crystals studied with a new coherent Raman scattering technique Chem. Phys. Lett. 147 18-24... 

One of the best available texts describing the principles of Raman scattering from crystals. Includes factor group calculations, polarization measurements, force constant calculations, and many other aspects of crystal physics. 

Fig. 2 Raman spectra of a single-crystal of orthorhombic Sg at three different polarizations in which the off-diagonal elements of the Raman scattering tensor are non-zero big, b2g, b g), after [105]. However, Raman intensities of other polarizations like flg components ( 54 cm ) penetrate in the spectra due to optical anisotropy in the crystal...

Denisov, V. N., Mavrin, B. N. and Podobedov, V. B. (1987) Hyper-Raman scattering by vibrational excitations in crystals, glasses and liquids. Phys. Rep., 151, 1-92. 

Tran [391,392] has reported ng detection of dyes on filter paper by SERS. Silver colloidal hydrosols stabilised by filter supports enhance the Raman scattering of adsorbed dyes. Typical detection limits are 500 pg (crystal violet), 7 ng (l,l,9-trimethyl-2,2 -cyanine perchlorate), 15 ng (3,3 -diethylthiacarbocyanine chloride) and 240 ng (methyl red) using a 3 mW He-Ne laser. 

Raman spectroscopy comprises a family of spectral measurements based on inelastic optical scattering of photons at molecules or crystals. It involves vibrational measurements as well as rotational or electronic studies and nonlinear effects. Following, Raman will be used in the established but slightly inaccurate way as a synonym for the most important and most common technique of the family, linear vibrational Raman scattering. 

Kitahara, K. Yamazaki, R. Kurosawa, T. Nakajima, K. Moritani, A. 2002. Analysis of stress in laser-crystallized polysilicon thin films by Raman scattering spectroscopy. Jpn. J. Appl. Phys. 41 5055-5059. 

The key requirements for ISRS excitation are the existence of Raman active phonons in the crystal, and the pulse duration shorter than the phonon period loq1 [19]. The resulting nuclear oscillation follows a sine function of time (i.e., minimum amplitude at t=0), as shown in Fig. 2.2e. ISRS occurs both under nonresonant and resonant excitations. As the Raman scattering cross section is enhanced under resonant excitation, so is the amplitude of the ISRS-generated coherent phonons. 

In addition to experiments which were possible with conventional lamps but can be much more easily performed with lasers, there are some investigations which have to be done within certain exposure times or signal-to-noise ratios and these have only been possible since lasers have been developed. This group includes the electronic Raman effect 195-197) observation of Raman scattering in metals where the scattering quasi particles are phonons, Raman studies of vibrational spectra in semiconductor crystals or the resonance Raman effect 200-202)... 

Probing Metalloproteins Electronic absorption spectroscopy of copper proteins, 226, 1 electronic absorption spectroscopy of nonheme iron proteins, 226, 33 cobalt as probe and label of proteins, 226, 52 biochemical and spectroscopic probes of mercury(ii) coordination environments in proteins, 226, 71 low-temperature optical spectroscopy metalloprotein structure and dynamics, 226, 97 nanosecond transient absorption spectroscopy, 226, 119 nanosecond time-resolved absorption and polarization dichroism spectroscopies, 226, 147 real-time spectroscopic techniques for probing conformational dynamics of heme proteins, 226, 177 variable-temperature magnetic circular dichroism, 226, 199 linear dichroism, 226, 232 infrared spectroscopy, 226, 259 Fourier transform infrared spectroscopy, 226, 289 infrared circular dichroism, 226, 306 Raman and resonance Raman spectroscopy, 226, 319 protein structure from ultraviolet resonance Raman spectroscopy, 226, 374 single-crystal micro-Raman spectroscopy, 226, 397 nanosecond time-resolved resonance Raman spectroscopy, 226, 409 techniques for obtaining resonance Raman spectra of metalloproteins, 226, 431 Raman optical activity, 226, 470 surface-enhanced resonance Raman scattering, 226, 482 luminescence... 

Kumazaki, T. Kito, Y. Sasaki, S. Kume, T. Shimizu, H. (2004). Single-crystal growth of the high-pressure phase II of methane hydrate and its Raman scattering study. Chem. Phys. Letter, 388 (1-3), 18-22... 

The soft-mode spectra in the FE phase was investigated within the same study [ 19] and a well-defined peak (S-peak) was found at 150 cm for T Tc as the lowest frequency peak in the spectra. The frequency of S-mode decreases with the increase in pressure, indicating that the S-mode is the soft mode and that the phase transition is of the displacive type, which is in accordance with the proton-tunneling model. Furthermore, Raman scattering experiments on deuterated crystals showed the disappearance of the S-peak in DKDP [20]. Since this phenomenon can also be explained by the protontunneling model, it is taken as another important piece of evidence for this model. 

Besides the peaks of the local proton modes typical for hydrogen bond, a sharp peak at 28 meV was observed in KDP [34] and attracted much attention [34,38,39]. This peak exists in DKDP at somewhat higher frequency its intensity decreases in both crystals and its width decreases upon the transition from the FE to the PE phase, without any softening of its frequency [38]. Hence, it is concluded that this mode is connected with the phase transition dynamics, i.e., coupled to the polarization fluctuations. This mode is not the tunneling mode or any local mode of proton or deuteron, but rather some collective optical mode of the lattice that involves substantial proton or deuteron displacement. It has been suggested [38] that this mode corresponds to the mode that has a peak at about 200 cm (25 meV) in Raman scattering and infrared reflectivity spectra, and that it is coupled to the soft mode and usually... 

Paulsen, H. N., HiUigse, K. M., Thgersen, J., Keiding, S. R., and Larsen, J. J. 2003. Coherent anti-Stokes Raman scattering microscopy with a photonic crystal fiber based light source. Opt. Lett. 28 1123-25. 

Watanabe, T, and Pettingger, B. 1982. Surface-enhanced Raman scattering from crystal violet adsorbed on a silver electrode. Chem. Phys. Lett. 89 501-7. 

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