Attempts to use the linear behavior of Raman spectroscopic measurements in operations such as spectral subtraction may be vitiated by abscissa errors which are smaller than one sampling interval. This paper describes methods, based upon least-squares fitting and Fourier-domain phase shifting, which can be used to locate the positions of peak maxima within 0.05 cm−1. A procedure is described to allow use of these determinations to shift the position of data sets along the X-axis by amounts less than one sampling interval. The effectiveness of this detection and correction procedure is demonstrated by measuring adjusted peak positions. Factor analysis is also used as a probe to examine the operation.
