Kinetic Analysis and Resolution of Overlapping EPR Spectra

A new method for the resolution and quantitative kinetic analysis of overlapping electron paramagnetic (EPR) spectra, based on a combination of smoothing by B-splines and/or discrete cosine transformation and linear algebra methods for finding eigenvalues and eigenvectors of the covariance matrix using the Frobenius normal form with subsequent final basis adjustment by the Moore–Penrose pseudo-inverse matrix, is proposed. This algorithm does not require the use of the time-consuming multiple iterations of the least squares method. Our approach has been tested on several specific chemical systems including stable organic radicals and paramagnetic V4+ and VO2+ ions. In all the cases, the analysis of experimental EPR spectra demonstrated that the new approach produces good results.