Surface Raman spectroscopy

Recent developments in Raman equipment has led to a considerable increase in sensitivity. This has enabled the monitoring of reactions of organic monolayers on glassy carbon [4.292] and diamond surfaces and analysis of the structure of Lang-muir-Blodgett monolayers without any enhancement effects. Although this unenhanced surface-Raman spectroscopy is expected to be applicable to a variety of technically or scientifically important surfaces and interfaces, it nevertheless requires careful optimization of the apparatus, data treatment, and sample preparation. 

Tian ZQ, Ren B, Mao BW. 1997. Extending surface Raman spectroscopy to transition metal surfaces for practical applications. 1. Vibrational properties of thiocyanate and carbon monoxide adsorbed on electrochemically activated platinum surfaces. J Phys Chem B 101 1338-1346. 

Hipps KW, Keder JK (1983) A direct comparison of surface Raman spectroscopy and inelastic electron tunneling spectroscopy. J Phys Chem 87 3187-3189... 

Surface and Interfacial Aspects of Biomedical Polymers, Vol. 1 Surface Chemistry and Physics, J.D. Andrade, Ed., Plenum Press (1985). (Contains chapters on XPS, surface infrared spectroscopy and surface Raman spectroscopy.)... 

Moskovits M, Dilella DP, Maynard KJ (1988) Surface Raman-spectroscopy of a number of cyclic aromatic-molecules adsorbed on silver - selection-rules and molecular-reorientation. Langmuir 4(l) 67-76... 

Figure 13.3. Two sampling geometries for surface Raman spectroscopy. (A) is 180° backscat-tering, and (B) uses a non-normally incident laser and normal collection through a window in a UHV chamber.

SURFACE RAMAN SPECTROSCOPY WITHOUT FIELD ENHANCEMENT... 

An early example of surface Raman without field enhancement is shown in Figure 13.7. This measurement predated the development of CCD detectors and represents a major achievement in terms of sensitivity (12). The adsorption of nitrobenzene on a well-defined nickel surface was carried out in UHV then Raman scattering was observed with a single spectrograph and an intensified Vidicon detector. Unenhanced spectra were obtained from 7.5 x lO molecules cm of nitrobenzene (1.1 x 10 " mol cm ), corresponding to a submonolayer. Examples of surface Raman spectroscopy with resonance enhancement include monolayers of phthalocyanines on gold (17) and ordered graphite (18), and multilayers of metalloporphyrins (19). 

Hines M. A., Harris T. D., Harris A. L. and Chabal Y. J. (1993), Looking up the down staircase surface Raman spectroscopy as a probe of adsorbate orientation , J. Electron Spectrosc. Relat. Phenom. 64—65, 183-191. 

Zhang Y, Edens G and Weaver M J 1991 Potential-dependent surface Raman spectroscopy of Buckminsterfullerene films on gold vibrational characteristics of anionic versus neutral CgQ J. Am. Chem. Soc. 113 9395-7... 

The discovery of a particular enhancement effect (up to 10 ) that affects only species in close contact with the metal electrode surface (i.e. adsorbed species) by Fleischmann et al. [352] and slightly later by Jeanmaire et al. [353] and a report on the utilization of resonance enhancement in surface Raman spectroscopy [354] demonstrated surprisingly the feasibility of vibrational studies of electrochemical... 

A. Campion, J.K. Brown, and V.M. Grizzle, Surface Raman-Spectroscopy Without Surface Enhancement, J. Vac. Sci. Technol. 20, 893 (1982)... 

P. Corio, P.S. Santos, V.W. Brar, G.G. Samsonidze, S.G. Chou, and M.S. Dresselhaus, Potential dependent surface Raman spectroscopy of single wall carbon nanotube films on platinum electrodes, Chem. Phys. Lett., 370, 675-682 (2003). 

This article first briefly surveys the history of Raman spectroscopy applied to electrochemistry, followed by a brief outline of the basic principles of surface Raman spectroscopy. The SERS phenomena and mechanisms are then introduced. This is followed by a detailed description of Raman instrumentation, and the... 

For readers interested in a comprehensive review of SERS, several excellent review articles with more detail on various aspects of the subject are recommended [13, 14, 25-29]. For recent progress in SERS, readers may refer to a special issue on SERS in the Journal of Raman Spectroscopy [31] and symposium proceedings on surface Raman spectroscopy [24]. 

Optical Fiber Raman Spectroscopy With the expansion of surface Raman spectroscopy, there is an increasing requirement on the measurement of systems in some very special environments, such as high temperature reactions, explosive, irradiative and combustible systems, or live animals. For the protection of the experimentahst and the instrument, an optical fiber technique is combined with Raman spectroscopy. Optical fibers can be employed to deKver the laser excitation source and collect the Raman signal with greater flexibility. As Raman is intrinsically a weak process, the major consideration of the optical fiber Raman system is to increase the collection efficiency. Typical systems consist of the laser, premonochromator, incident optical fiber, collection optical fiber, and the spectrograph. Additional adaptors are needed to... 

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