Estimates of Absolute Ion Shieldings from Relaxation Rates and Solvent Isotope Shifts

Estimates of Absolute Ion Shieldings from Relaxation Rates and Solvent Isotope Shifts 

Deverell [245] has proposed three methods, which do not involve theoretical calculations of halide crystals, to estimate absolute nuclear shielding data of aqueous alkali and halide ions. The first method is based upon the experimental observation of a dependence of aqueous alkali ion and halide ion shieldings upon the isotopic composition of the solvent. The NMR signals of these ions are shifted towards higher fields as the mole fraction of deuterium in the solvent increases (see further Section 6.5). This solvent isotope shift which is particularly notable for the halide ions is attributed to the altered vibration pattern of the hydrated ions in turn affecting the energy difference between excited states and the ground electronic state [369], The U.V. 

Deverell also analyzes the relationship between the time modulated field gradient and i,e, the paramagnetic contribution to 

In infinitely dilute aqueous solutions the relaxation rates are, according to Deverell, related to by Eq. (5.7) in Section 5.1. 

Values of t are taken as reorientation times from relaxation data c 

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