EXAFS BACKGROUND SUBTRACTION USING SPLINES

An improved background subtraction technique using cubic splines is presented. With this method one is able to suppress oscillations of the spline background by varying a tuning parameter. By changing this tuning parameter one can control the amount of a positive quantity, related to the curvature of the background function, that is added to the chi(2) sum for a given spline background. Minimizing the sum of squares plus the positive term results in very good background fits and even complicated data can be handled. Furthermore, incorporated in the algorithm is the additional capability to reduce, or even remove, sudden jumps in the data, which may have been caused by multiple diffraction in the single-crystal monochromator.