Ultraslow atomic motion by site-selective excitation of highly resolved nuclear magnetic resonance lines in dilute spin systems.

Site-selective excitation of NMR spectra is a powerful tool for measuring directly the transport of nuclear magnetization via atomic diffusion. The method has been applied to measure self diffusion parameters in single crystalline Tellurium, Selenium and titaniumdioxide. Atomic jump rates as low as 0.001/s have been determinated (Se). A comparison with the respective macroscopic diffusion data (tracer, electr. conductivity) allowed a determination of the underlying diffusion mechanisms. It is shown hat in Ti02 (rutile) the monovacancy diffusion mechanism on the Ti-sublattice contributes with about 1 % to the overall titanium mobility.