Micro Raman

Turrell G and Dhamelincourt P 1996 Micro-Raman spectroscopy Modern Techniques in Raman Spectroscopy ed J J Laserna (New York Wiley) pp 109-42... 

However, as Raman scattering is a two-photon process, the probability of the Raman scattering process is lower than that of fluorescence and IR absorption processes. The cross section of Raman scattering is 10 cm, which is much smaller than that of fluorescence ( 10 cm ) and IR absorption ( 10 °cm ). When we detect Raman scattering at the nanoscale, the number of photons obtained is less than with the usual micro-Raman spectroscopy due to reduction in the detection area or the number of molecules. To overcome this problem, we need to devise a method for amplification of Raman scattering. 

Figure 2.6 Raman spectrum of an adenine nanocrystal obtained (a) with and (b) without the metallic tip. Spectrum (a) corresponds to the tip-enhanced near-field Raman spectrum while spectrum (b) shows the conventional micro-Raman spectrum.

In Raman measurements [57], the 514-nm line of an Ar+ laser, the 325-nm line of a He-Cd laser, and the 244-nm line of an intracavity frequency-doubled Ar+ laser were employed. The incident laser beam was directed onto the sample surface under the back-scattering geometry, and the samples were kept at room temperature. In the 514-nm excitation, the scattered light was collected and dispersed in a SPEX 1403 double monochromator and detected with a photomultiplier. The laser output power was 300 mW. In the 325- and 244-nm excitations, the scattered light was collected with fused silica optics and was analyzed with a UV-enhanced CCD camera, using a Renishaw micro-Raman system 1000 spectrometer modified for use at 325 and 244 nm, respectively. A laser output of 10 mW was used, which resulted in an incident power at the sample of approximately 1.5 mW. The spectral resolution was approximately 2 cm k That no photoalteration of the samples occurred during the UV laser irradiation was ensured by confirming that the visible Raman spectra were unaltered after the UV Raman measurements. 

Applications Sollinger and Sawatzki [793] have reported the use of TLC-Raman for routine applications, e.g. TLC of hydroxybenzenes (including hydro-quinone and pyrogallol) on conventional, silica gel and specific Raman-TLC plates (coated with spherical silica gel). Databases were used for identification of substances. Typical detection limits were in the low p,g region per application, Micro-Raman spectrometry has been employed in analysing TLC fractions from polymer additives within a detection limit... 

Figure 3.7. Schematic diagram of the basic layout of the apparatus typically employed in micro-Raman spectrometers, or microprobes. (From Turrell and Corset 1996.)...

As an example of the application of joint micro-LIBS and micro-Raman analysis on actual samples, results are reported on the study of a small fragment (less than 1 mm2) of the S.Antonio Abate , a wooden painted artwork decorating the Arciconfratemita della Misericordia in Siena, attributed to the Renaissance Italian artist Domenico di Pace, also known as II Beccafumi (Montaperti 1486 - Siena 1551). The sample, whose dimensions were relatively small (less than 1 mm2), was given by Opificio delle Pietre Dure di Firenze (OPD) to the Department of Chemistry of Pisa University, where it was going to be analysed for the presence of lakes in the... 

In Figure 3 is shown the experimental set-up used for micro-Raman measurements. 

Since LIBS analysis doesn t give information about the molecular composition of the pigments, a micro-Raman analysis was performed for an exact characterization of the sample. 

Bicchieri M., Nardone M., Russo P.A., Sodo A., Corsi M., Cristoforetti G., Palleschi V., Salvetti A., Tognoni E., Characterization of azurite and lazurite based pigments by LIBS and micro-Raman spectroscopy, Spectrochim. Acta B 2001 56 915-922. 

Bussotti L., Castellucci E., Matteini M., The Micro-Raman Technique in the Studies for the Conservation of Art Works Identification of Lakes in Paints, Science and Technology for Cultural Heritage 1996 5 (1) 13. 

Wall painting in the Messer Filippo cell, Tower of Spilamberto (Modena, Italy). The painted surface is in an advanced state of deterioration the detachment of the pictorial matter from the plaster is evident, efflorescence is present, and the pictorial coating is almost completely covered by a grey-whitish film formed by microcrystalline gypsum, as proved by micro-Raman investigations. The FA profile, characterized by an A/P ratio of... 

D. Bersani, P.P. Lottici, A. Casoli, D. Cauzzi, Pigments and Binders in Madonna col Bambino e S. Giovannino by Botticelli Investigated by Micro Raman and GC/MS, Journal of Cultural Heritage, 9, 97 102 (2008). 

P. Vandenaheele, B. Wohling, L. Moens, H. Edwards, M. De Ren and G. van Hooydonk, Analysis with micro Raman spectroscopy of natural organic binding media and varnishes used in art, Anal. Chim. Acta, 407, 261 274 (2000). 

K. Shen, S. Curran, H. Xu, S. Rogelj, Y. Jiang, J. Dewald, and T. Pietrass, Single-walled carbon nanotube purification, pelletization, and surfactant-assisted dispersion a combined term and resonant micro-Raman spectroscopy study. J. Phys. Chem. B 109, 4455 1463 (2005). 

J.S. Kim, P.K.H. Ho, C.E. Murphy, N. Baynes, and R.H. Friend, Nature of non-emissive black spots in polymer light-emitting diodes by in-situ micro-Raman spectroscopy, Adv. Mater., 14 206-209, 2001. 

Micro-Raman spectroscopy Crystal phase structure, crystal size, surface metal oxide structure and coverage Trained Free... 

The lateral surfaces of the samples were polished to allow micro-Raman profiling measurements. 

S.-Y. Lin, W.-T. Cheng and S.-L. Wang, Thermal micro-Raman spectroscopic study of polymorphic transformation of famotidine under different compression pressures, J. Raman Spectrosc., 38, 39 3 (2007). 

W. Schabel, I. Ludwig and M. Kind, Measurements of concentration profiles in polymeric solvent coatings by means of an inverse confocal micro Raman spectrometer - Initial results. Drying Technol., 22, 285-294 (2004). 

D. Hill, T. Jawhari, J.G. Cespedes, J.A. Garcia and E. Bertran, In-situ monitoring of laser annealing by micro-Raman spectroscopy for hydrogenated silicon nanoparticles produced in radio frequency glow discharge, Phys. Status SolidiA, 203, 1296-1300 (2006). 

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... 

G. Penel, G. Leroy, C. Rey, E. Bres, Micro-Raman spectral study of the PO4 and CO3 vibrational modes in synthetic and biological apatites, Calcif. Tissue Int. 63 (1998) 475-481. 

Campos, F. J., et al., Confocal Micro-Raman Scattering and Rutherford Backscattering Characterization of Fattice Damage in Aluminum-Implanted 6H-SiC, Diamond and Related Materials, Vol. 9, 1999, pp. 357-360. 

Schrader, B., Micro Raman, Fluorescence, and Scattering Spectroscopy of Single Particles, in Physical and Chemical Characterization of Individual Airborne Particles (K. R. Spurny, Ed.), Chap. 19, pp. 358-379, Ellis Horwood, Chichester, 1986. 

Bukalov SS, Mikhalitsyn LA, Zubavichus YaV et al (2006) Investigation of the structure of graphite and other sp2 materials by means of micro-Raman spectroscopy and x-ray diffraction. Russian Khim Zh l(l) 83-87 [in Russian]... 

We developed a micro-Raman probe (MRP) with a total diameter of 600 pm to use with an intravascular endoscope [28]. To develop this MRP, it was important to consider the following three parameters when selecting the optical fiber (1) f b, (2) NA, and (3) core diameter. The first parameter... 

With the help of a micro-Raman setup the laser spot can be focused down to about 1 pm in diameter. This allows for the differentiation of single bacterial cells or a biochemical analysis of subcellular components within bacterial (diameter approx. 1 pm) or yeast cells (diameter approx. 5-10pm). A confocal Raman setup achieves an even better spatial resolution [6, 7]. This possibility enables Raman mapping or imaging experiments with spatially resolved information of the whole sample in axial and lateral directions. 

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