We prepared ultrafine germanium particles by gas-evaporation techniques. The particle composition was studied by Raman and x-ray scattering. We take an analytical model to explain the Raman profile: the particle is composed of a single-crystalline core and a coating amorphous shell. In this single-crystalline part, the phonon mode is completely localized, and as a result the red shift and the broadening of the Raman signal are induced. We introduce a localization factor to describe the size effect. According to this model we determined the mean diameter of a crystalline particle. The result is compared with that from x-ray diffraction. Our results indicate that the coating amorphous shell thickness is nearly constant, although the crystalline particle size varies by the evaporation-gas pressure. Furthermore, we found that the Raman profile changes by the wavelength of the exciting laser.

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This paper describes the liquid-crystalline properties of alkyl 4-[2-(perfluorooctyl)ethoxy]benzoates (1) and bromo (2) and nitro (3) substituted compounds. For 1, the lower members show a smectic A phase; also the smectic A-isotropic transition temperatures and the latent heats decrease with increasing the carbon number of the hydrocarbon chain. An X-ray examination indicated that the smectic A phase has an interdigited arrangement of molecules. The results are discussed in terms of inter- and intra-layer fluorophilic interactions around the perfluorooctyl groups.

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