Synchrotron-based infrared microscopic measurements have been performed on various hair transverse sections, sampled either from the heads of Caucasian or Afro-American subjects. Lipid content of various virgin hair transverse sections was established, with an unprecedented resolution. The variations in shape and intensity of the CH(2), CH(3), amide I and amide II bands, before and after lipid removal by solvent extraction, were profiled, showing clearly that Caucasian hair often contains lipids localized inside the medulla and to a lesser extent inside the cuticle. This statement does not hold for the Afro-American hair analysed. For this, the FT-IR spectra do not change within the hair section and are insensitive to solvent extraction. The importance of the origin of hair on its physical and chemical properties has to be taken into account in future investigations.

The potentiality of synchrotron infrared microspectrometry was investigated for in situ analysis of fluid inclusions and volatiles of particular geological interest. Thanks to the intrinsic high brightness of the synchrotron infrared source, areas as small as a few μm2 can be probed, providing a high-contrast analysis of small inclusions in geological materials. We have identified organic components in such small volumes in their liquid and gaseous phase, thus allowing a deeper analysis of oil-water inclusions entrapped in diagenetic cements. Such detailed analysis opens up new perspectives in petroleum reservoir evolution studies. The high signal-to-noise ratio of spectra obtained in small volume allows a fast and accurate chemical mapping of the inclusion components. Drastic refraction effects preclude, at the present state, a quantitative analysis of either the volume or the thickness of the individual inclusions. Traces of volatiles such as CO2 and H2O are easily detected in the vitreous and gaseous part of the glass melt fluid inclusions. We have also profiled the hydroxyl concentration near a wall, and calculated the hydrogen diffusion coefficient in anhydrous minerals such as diopside.

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Synchrotron infrared studies of adsorbates on surfaces offer the possibility of probing low-frequency vibrational modes and dynamics at high resolution (l cm I, 125 p.,eV). Extensive experiments have been performed for ordered submonolayers of CO on low index Cu surfaces [U3X~3)R30° COl CuOll), c(2x2) CO/Cu(lOO) and (1 X2) CO/Cu(llO)], in the 100-2500 cm-\ (~12.5-312,5 mcV) range, These are the first IR experiments to directly probe the adsorbate-substrate vibrations for this system. In addition, however, several surprising features are observed including the dipole-forbidden hindered rotation and an unexpected broadband absorption. 'I\vo theories have been motivated by this work, and will be compared to our experimental results. The first theory is a cluster calculation by Tully, Gomez, and Head-Gordon, which takes into account the breakdown of the Born-Oppenheimer approximation and predicts lifetimes and frequencies of the vibrational modes for CO/Cu(100). Another Dmde-based theory, proposed by Persson, considers the coupling of the conduction electron current to the vibrations of the adsorbates, accounting for the observation of both the broadband absorption and dipole-forhidden peak.