The effect of bulk magnetic susceptibility (BMS) on solid state NMR spectra of paramagnetic compounds was investigated theoretically and experimentally. The BMS shift was calculated for cylindrical and spherocylinderical containers with some ratios of the length L and the diameter D. The results sho
Effect of Paramagnetic Ions on NMR Relaxation of Fluids at Solid Surfaces
โ Scribed by I. Foley; S.A. Farooqui; R.L. Kleinberg
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 204 KB
- Volume
- 123
- Category
- Article
- ISSN
- 1064-1858
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โฆ Synopsis
Proton NMR longitudinal and transverse relaxation times of water-saturated powder packs have been measured. The powders were a series of synthetic calcium silicates with known concentrations of iron or manganese paramagnetic ions. The rate of water proton relaxation has been found to be linearly proportional to the concentration of paramagnetic ion. The constant of proportionality is used to determine the electron relaxation time of ions at the fluid-solid interface. A substantial relaxivity is found in the absence of paramagnetic ions. Thus the oxide surface itself is an unexpectedly good relaxer of fluid-borne nuclear spins. The results answer some long-standing questions connected with the NMR properties of fluid-saturated sedimentary rocks.
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