Temperature dependence of methyl reorientation at intermediate hindering potentials.

Abstract

Spin conversion and spin-lattice relaxation measurements are performed on four methyl compounds, chosen so as to have almost equally high hindering potentials for the methyl reorientation. The relaxation data are analyzed to give two characteristic parameters of this motion: ${\mathrm{\ensuremath{\omega}}}_{\mathit{t}}$, the frequency of the coherent tunneling, and ${\mathrm{\ensuremath{\tau}}}_{\mathit{c}}$, the correlation time of the thermally assisted methyl reorientation. The temperature dependence of both parameters is discussed and a comparison is made for the four samples studied.