Es wird ein Überblick über die bisher vorliegenden Kernresonanzuntersuchungen in der Nähe kritischer Zustände in fluiden, überwiegend organischen Einund Zweistoffsystemen ( ;z.B. Methanol‐Csz, n‐Heptan‐Perfluormethylcyclohexan, Triäthylamin‐Wasser) gegeben.
Diffu.vion / / I Fustkiirper ! Magnetische KernresonanzNuclear spin-lattice relaxation rates and nmr absorption linewidths of 'H and 'Li in solid LiH have been measured up to 620°C. For both species motional narrowing is observed which is shifted under the influence of MgH, additions in opposite directions. Above 300°C spinlattice relaxation is exclusively determined by dipole interactions originating from translational diffusion. The calculated peak relaxation rates are in excellent agreement with the observed ones. -For LiH containing Li,O or small additions of MgH2, the mean jump frequency of hydrogen by far exceeds that of lithium in the whole temperature range. Between 400 and 620°C for LiH in equilibrium with Li,O the mean jump frequencies are given by v(H) enthilt in diesem Fall wahrscheinlich einen erheblichen Beitrag des Platzwechsels uber assoziierte Leerstellen (der bei der Leitfahigkeit fehlt). Fur einen derartigen Beitrag zur Diffusion ist ein Kernresonanz-Korrelationsfaktor zu erwarten, der halb so groD ist wie der entsprechende Korrelationsfaktor fiir die Tracer-Diffusion.
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