An NMR study of molecular reorientation processes in solid n-butane

Abstract

Proton magnetic resonance line shapes for polycrystalline n-butane have been studied over the temperature interval 20 K to the melting point. Spin–lattice relaxation time measurements have been made in the low temperature solid phase but no minimum found. The results show that methyl group tunneling persists to very low temperatures at a rate sufficiently high to narrow the absorption spectrum. In the high temperature solid phase long axis rotational motion of the molecules occurs. A model for this form of motion is discussed.