Factors affecting quantitative analysis using Raman and resonance Raman spectroscopy.

摘要

This work deals with the quantitative use of Raman and resonance Raman spectroscopies. The types of difficulties that occur when using these spectroscopies are due to the many factors that affect Raman signals. In Chapter I, the general principles of Raman spectroscopy are discussed which include a description of the instrumentation, a comparison to IR spectroscopy, and a brief overview of the factors that affect the Raman signal.; The determination of azo dyes by resonance-enhanced Raman spectroscopy discussed in Chapter II describes the use of an internal standard to correct the Raman signal for fluctuations in excitation radiation power, optical alignment, and absorbance. Also, the use of frequency exclusion in the Fourier domain and data domain truncation to exclude fluorescence from the Raman signal will be discussed. Limits of detection in the parts-per-billion range are reported due to the resonance enhancement effect.; The use of Raman spectroscopy to detect and determine the concentration of minor components in a nominally pure solid is given in Chapter III. Background removal is accomplished through the use of an abscissa correction. Cross-correlation and least-squares fitting are used for quantitation to obtain limits of detection near 0.1%. Simulations are used to demonstrate how an iterative least-squares fitting program can be used to detect previously unknown impurities.; The effect of absorbance of the incident and scattered radiation on the Raman signal is discussed in Chapter IV. A correction set is derived that is based on an earlier work, but now includes a correction for the collection efficiency of the collecting optics and allows the user to apply the actual physical dimension of the path length.; In Chapter V, the use of a KrF excimer laser as the exciting source in a UV resonance Raman system is discussed. The generation of new lines in the UV by stimulated Raman scattering is described. Also, the problem of saturation and techniques to avoid its effects are discussed.