PULSED NUCLEAR MAGNETIC RESONANCE IN ALKTI HALIDES
Abstract
Free induction decay and quadrupolar echo shapes showing the dependence of quadrupolar broadening on the orientation of the crystal relative to the external magnetic field were measured. In all substances studied, quadrupolar broadening disappears at high temperatures. The disappearance is interpreted as arising from the annealing of dislocations, which reappear when the crystal is cooled to room temperature. At temperatures on the order of 600 K diffusion increases the free induction decay lifetimes; at still higher temperatures, free induction decay lifetimes decrease. This decrease is tentatively ascribed to quadrupolar broadening by vacancies. Calculations of the effects of diffusion on the quadrupolar part of free induction decay and echo shapes are presented. These calculations show that diffusion will slow the decay of the quadrupolar part of a free induction decay and attenuate, broaden, and delay the appearance of a quadrupolar echo. A method for the separate measurement transitions in a spin 3/2 system subject to quadrupolar relaxation but not a spin temperature constraint is proposed. The spin echo apparatus used for the experiments is described in detail. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1961
- Accession Number
- AD0267593
Entities
People
- W.g. Clark
Organizations
- Cornell University