Self-Diffusion in Quasicrystals and Electronic States and Melting of III-V Semiconductor Nanocrystals: A Nuclear Magnetic Resonance Study

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9520477 Wu Nuclear magnetic resonance (NMR) measurements will be carried out to identify and characterize atomic motion with an anomalously low activation energy in quasicrystals. Such measurements will also be used to improve the crystallinity of noninteracting semiconducting nanoparticles and to detect the melting of such nanocrystals. The NMR technique will also be used to characterize quantum confinement and interband optical excitation in noninteracting semiconducting nanocrystals. %%% Quasicrystals are known for possessing a new type of long range order that differs from that of perfectly ordered structures like common salt. A new type of atom motion is predicted to occur in quasicrystals -- but has not yet been observed. The current measurements using magnetic resonance techniques will attempt to investigate this phenomenon. In addition, ultrasmall particle called nanocrystals will be investigate with special focus on the changes occurring in physical properties due in part to the effect of the small size of the particles. One effect that will be investigated is the change in the melting of such crystallites. ***