Some nuclear resonance properties of nearly free methyl rotors in the solid state

Abstract

This paper is primarily concerned to show how nuclear resonance can be used to investigate the rotational energy states and transition rates of weakly hindered symmetric rotors in the solid state, while at the same time developing an explanation for the nuclear resonance data from the methyl protons in CH₃LiCOO · 2D₂O. The discourse introduces the ideas involved in the context of a simple threefold free rotor, before extending them first to a weakly hindered rotor and then to a pair of coaxial rotors. The kernel is that by exploiting the angular variation of temperature and frequency dependent studies, experimental data of sufficient precision are available to enable meaningful molecular information to be obtained. Though space restricts this presentation to a limited explanation of the spectrum, quantitative derivations from transient signals and relaxation data will be presented for discussion.