Year: 1957
Type: article
Abstract: A theoretical treatment is given of the Overhauser effect in solids containing two or more different nuclear species. In a rigid lattice a decrease is predicted in the macroscopic magnetic moment of one nuclear species on saturating the spin system of the other. In a lattice executing internal motion the Overhauser effect is shown to be strongly dependent upon the value of the lattice correlation time. The usual assumption of the temperature dependence of this correlation time allows one to predict the variation of the Overhauser effect with temperature. The theoretical results are compared with experiment. Good agreement is obtained for the temperature dependence of the Overhauser effect in phosphonium iodide. Agreement in ammonium fluoborate could be obtained only on the assumption that the `internal' relaxation of the spins in the ammonium ion is small compared with the `external' relaxation processes. At low magnetic field strengths lithium fluoride exhibited the expected behaviour of the Overhauser effect in a rigid lattice.
Author: W A Little
Institution: University of Glasgow
Language: English
Subfield: Spectroscopy
Field: Chemistry
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2073917649