Anelastic processes in calix[n]arene-type organic molecules

We measured the anelastic spectrum of two organic molecules, calix[4]arene and p-tert-but-calix[4]arene. In both samples, a peak observed around 45-60 K for a measurement frequency of about 1 kHz was ascribed to the hopping of H atoms of the O-H groups, due to the close similarity of the physical parameters of these peaks with those obtained by a NMR relaxometry study. The present results reveal that anelastic spectroscopy is a good tool for studying atomic motion inside molecules at a mesoscopic level.