Characterization of organosulfur molecular monolayers on au(111) using scanning tunneling microscopy

Theory of Raman scattering evolution and revolution of Raman instrumentation - application of available technologies to spectroscopy and microscopy Raman spectroscopy and its adaptation to the industrial environment Raman microscopy - confocal and scanning near-field Raman imaging the quest for accuracy in Raman spectra chemometrics for Raman spectroscopy Raman spectra of gases Raman spectroscopy applied to crystals - phenomena and principles, concepts and conventions Raman scattering of glass Raman spectroscopic applications to gemmology Raman spectroscopy on II-IV-semiconductor nanostructures medical applications of Raman spectroscopy - in vivo Raman spectroscopy some pharmaceutical applications of Raman spectroscopy low-frequency Raman spectroscopy and biomolecular dynamics - a comparison between different low-frequency experimental techniques collectivity of vibrational modes Raman spectroscopic studies of ion-ion interactions in aqueous and non-aqueous electrolyte solutions environmental applications of Raman spectroscopy to aqueous solutions Raman and surface enhanced resonance Raman scattering - applications in forensic science application of Raman spectroscopy to organic fibres and films applications of IR and Raman spectra of quasi-elemental carbon process Raman spectroscopy the use of Raman spectroscopy to monitor the quality of carbon overcoats in the disk drive industry Raman spectroscopy in the undergraduate teaching laboratory Raman spectroscopy in the characterization of archaeological materials.

Handbook of Raman Spectroscopy: From the Research Laboratory to the Process Line

Analysis of organic polymorphs. A review

Although the physics of Raman spectroscopy and its application to purely chemical problems is long established, it offers a noninvasive, nondestructive, and water-insensitive probe to problems in the life sciences. Starting from the principles of Raman spectroscopy, its advantages, and methods for signal enhancement, the bulk of the review highlights recent applications. Structural investigations of a hormone receptor, testing the biocompatibility of dental implants, probing soil components and plant tissue alkaloids, and localization of single bacteria are just four problems in which Raman spectroscopy offers a solution or complements existing methods.

Raman Spectroscopy—A Prospective Tool in the Life Sciences

Resonance Raman (RR) spectroscopy has several advantages over the normal Raman spectroscopy (RS) widely used for in situ characterization of solid catalysts and catalytic reactions. Compared with RS, RR can provide much higher sensitivity and selectivity in detecting catalytically-significant surface metal oxides. RR can potentially give useful information on the nature of excited states relevant to photocatalysis and on the anharmonic potential of the ground state. In this critical review a detailed discussion is presented on several types of RR experimental systems, three distinct sources of so-called Raman (fluorescence) background, detection limits for RR compared to other techniques (EXAFS, PM-IRAS, SFG), and three well-known methods to assign UV-vis absorption bands and a band-specific unified method that is derived mainly from RR results. In addition, the virtues and challenges of surface-enhanced Raman spectroscopy (SERS) are discussed for detecting molecular adsorbates at catalytically relevant interfaces. Tip-enhanced Raman spectroscopy (TERS), which is a combination of SERS and near-field scanning probe microscopy and has the capability of probing molecular adsorbates at specific catalytic sites with an enormous surface sensitivity and nanometre spatial resolution, is also reviewed (300 references).

Resonance Raman and surface- and tip-enhanced Raman spectroscopy methods to study solid catalysts and heterogeneous catalytic reactions

Using a commercial Fourier transform infrared spectrometer and the 1.064μm line of a CW Nd∶YAG laser, we have measured the Raman spectra of a wide variety of materials. The Raman scattered light, Stokes shifted toward the mid-infrared, is collected, using a 90° lens geometry, and focused through the emission port of the spectrometer. After passing through the Michelson interferometer, the light is detected by a thermoelectrically-cooled high-sensitivity germanium detector. The Fourier transform of the resulting interferogram gives the Raman spectrum. This new technique allows spectra to be obtained of samples which were previously completely masked by competing fluorescence. In addition, FT-Raman also allows moieties, such as hydrocarbon chains, which are not present in resonance enhanced spectra, to be investigated. We will discuss our approach toward FT-Raman, which is compatible with traditional Raman spectroscopy, present representative spectra of liquids and solids, and draw some comparisons and contrasts between dispersive and FT measurements.

Experimental aspects of Fourier transform Raman spectroscopy

Recently we have combined infrared spectroscopy and atomic resolution scanning tunneling microscopy (STM) to probe the local structure and intermolecular arrangement of molecules within thin films. IR spectroscopy provides spatially averaged information about orientation of the molecules with respect to the surface and about intermolecular arrangement within the crystallographic unit cell. STM data yields a local picture of molecular packing within the film. The requirements of an atomically flat (over distances of hundreds of angstroms) conducting substrate for the STM are fulfilled by an epitaxially grown film of gold on a cleaved mica substrate which also provides a good infrared reflective surface, enabling IR and STM measurements on identical samples. Systems investigated include Langmuir-Blodgett films of cadmium arachidate and self-assembled films of octadecyltrichlorosilane.

Structure and topography of molecular assemblies on solid substrates by infrared spectroscopy and scanning tunneling microscopy

Structural studies of Langmuir-Blodgett monolayers and multilayers have revealed that both the hydrophilic and the hydrophobic parts of an amphiphilic molecule can influence the exent of 2-dimensional packing which occurs within a film. In particular, dye chromophores to which are appended long hydrocarbon tails will usually form films dominated by the interaction of the chromophores unless a small amount of hydrocarbon liquid is added. In this case the packing will be dominated by the intermolecular interaction of the hydrocarbon tails. FT-Raman studies of these amphiphilic molecules provides information about both parts of the molecule without resonance enhancement since the laser wavelength used for excitation is far removed from any absorption maxima of the dye chromophore. Specific examples of thiocyanine and merocyanine dyes will be discussed.

Vickie M. Hallmark

Papers

Experimental aspects of Fourier transform Raman spectroscopy

Structure and topography of molecular assemblies on solid substrates by infrared spectroscopy and scanning tunneling microscopy

FT-Raman studies of langmuir-blodgett monolayer components containing absorbing chromophores