Analysis of photon correlation spectral decay curves by the S-exponential sum method

Abstract

The analysis of decay curves by the fitting of sums of positive exponentials by the S-exponential sum method of Cantor and Evans is considered. The method has significant advantages over previous methods in guaranteeing the uniqueness of the derived set of positive amplitude exponentials, which provide the best weighted least-squares fit to the data, and in not requiring prior estimates of the number or the values of the decay constants. This paper treats the case of analysis of a single exponential with background and varying noise levels. A comparison of the accuracy obtainable using the C–E method and the Marquardt least-squares procedure is made. The application of this analysis to photon correlation spectroscopy is discussed.