Identification of Hidden Relaxations by Even-Order Derivative Spectroscopy

The effectiveness of fourth-order derivative spectroscopy has been recently demonstrated, from a mathematical point of view and by illustrating its application in a number of case studies. In this work, the usefulness of the technique is shown by focalizing on the application to a couple of "difficult" cases taken from the literature, and its applicability limits are discussed on a simulated water-ethanol solution. A Python code for the dielectric relaxation analysis has been released as a free tool for relaxation identification.