POLARIZATION MEASUREMENTS IN NEAR-INFRARED FOURIER-TRANSFORM SPECTROSCOPY

In principle, Raman measurements provide information about vibrational frequencies and intensities. Working with polarized light provides additional information about the Raman scattering tensor components. The special conditions relating to the near-infrared-Fourier transform (NIR-FT) Raman technique may preclude adaptation of some of the techniques employed for measurements with linear polarized light in 'classical' Raman spectroscopy in the visible range. The experimental conditions for measurements of depolarization ratios of liquids (benzene, mesitylene, p-xylene and carbon tetrachloride) using different experimental geometries with an NIR-FT-Raman spectrometer were elucidated. The FT technique allows the rapid and simple determination of depolarization ratios with a quality sufficient to assign the bands to totally or non-totally symmetric species. The possibility of determining the orientation of molecules in non-crystalline solids is also demonstrated. Finally, the feasibility of measuring the different components of the Raman scattering tensor of a single crystal of sodium chlorate is considered.