Quantitative laser Raman spectroscopy on colored substances is considered, and it is shown that sample positioning and concentration are less critical when 180° illumination is used in place of the more common 90° illumination. In addition, the correction of Raman intensities for sample absorption is easily accomplished for data collected via backscattering (180° geometry), and the appropriate equations are presented. A spinning sample cell and holder are described for 180° illumination. The design utilizes simple and inexpensive sample tubes which are conveniently employed with standard liquids and solids as well as volatile, air-sensitive, and corrosive compounds. Provision for sample heating and cooling is described.
D. F. Shriver and J. B. R. Dunn, "The Backscattering Geometry for Raman Spectroscopy of Colored Materials," Appl. Spectrosc. 28, 319-323 (1974)