  The anelastic spectrum of calix[4]arene was measured at two different
vibrational frequencies. Three thermally activated peaks were detected. The
lowest temperature peak can be described considering a continous distribution
function of activation energies for the relaxation. This anelastic peak can be
ascribed to a thermally activated hopping process of H atoms of the OH groups,
corresponding to a flip-flop of the OH bond. From the results of the present
study, it seems that anelastic spectroscopy is a good experimental technique to
study atomic motion inside molecules at a mesoscopic (few molecules) level.
