Abstract by Emma Carlsen
Chemistry and Biochemistry
Characterization of Intermolecular Interactions in Water and Simple Alcohols Using Impedance Spectroscopy
Electrochemical Impedance spectroscopy (EIS) can reveal important qualities of intermolecular interactions in water and other dielectric fluids, including those attributed to hydrogen bonds. One of the features described as a Debye-like relaxation in the spectra of water and chemically similar compounds is explained by rotational reorientations. In this study, we collected spectra of water and simple alcohols from 20 Hz – 18 GHz, over a range of temperatures to explore alternative explanations. As the aspect ratio of the molecules increases and the likelihood of rotations decreases, the spectra show a similar relaxation mechanism where increasing conductivity must be explained through ionic translations rather than rotations. From this, the ionic concentration is calculated from the conductivity plateau following the relaxation, rather than the DC conductivity preceding it. This gives ionic concentrations orders of magnitude greater than the currently held 10-7 M. A higher ionic concentration provides explanations for properties of water previously attributed exclusively to hydrogen bonds and has implications on the suitability of the pH scale.