A Reevaluation of the Ultrasonic Absorption Spectra of Aqueous Samarium(III) Sulfate Solutions.

摘要

Measurements of the ultrasonic absorption spectra of aqueous samarium sulfate solutions have been repeated using an optical-acoustic method over the frequency range 15-250 MHz. Considerably more data points were obtained with the new method, and the data have been analyzed in terms of a single and a double relaxation over both a constant and a variable nonrelaxational background absorption. The double relaxation analyses provide the best correspondence between theory and experiment. The overall ion association process has been treated as a two-step kinetic mechanism yielding four rate constants correlated with both relaxation times. The results are discussed in terms of the internal consistency of the two-step model. Comparisons are made with theoretical predictions of the rate constants for the diffusion-controlled first step and with previously reported values for the rate constants for the second and rate-determining step. (Author)