Polarised radiation studies with orientation

Since the parallel components of the dynamic dipole are active in RAIRS, it is possible to use the azimuthal dependence to obtain the orientation of the adsorbate at the surface. A similar technique has been applied to adsorbates on metals in HREELS measurements made off specular in order to observe parallel modes through impact or resonant scattering processes. This was first demonstrated for the Rh(CO)2 molecule on anisotropic TiO2(110) surface [72]. The results of this study also allow a test of the three layer model theory (Fig.5,6) as applied to S-polarised radiation. Fig. 11 shows the FT-RAIRS spectrum for 1/3 monolayer of Rh(CO)2 on Ti02(l 10) measured with P and S polarised radiation. 

Much attention has been given to the analysis of OH stretching bands of micas occurring in an isolated region of the spectrum ranging from about 3750 to 3550 cm (Farmer 1974). Using polarized radiation, the pleochroic scheme of IR absorption bands, measured on oriented crystal sections, makes it possible to impose defined constraints on the orientation of the OH dipoles. In a fundamental polarised IR study, Tsuboi (1950) determined the position of the H atom in the structure of muscovite. The variation of absorption intensity of the OH stretching band with the direction of the electric vector of... 

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