Search results for "Topaz"
showing 4 items of 4 documents
Optical properties of natural topaz
2013
The results of investigation of infrared, Raman and UV-Visible absorption spectra of natural topaz crystals from Ukraine before and after fast neutron irradiation are presented. We assume that the ~ 620 nm band in topaz crystals is associated with the presence of Cr 3+ , Fe 2+ and Mn 2+ impurities. The broad band with maxima at 650 cm -1 observed in Raman spectra for topaz irradiated by fast neutrons may be connected with lattice disorder. Exchange interaction between radiation defect and impurity ions during neutron irradiation leads to appearance of additional absorption band in UV-VIS spectra and bands broadening in infrared and Raman spectra of investigated crystals.
Analysis of the cleaved topaz (001) surface.
2003
We report on the first study of the cleaved (001) topaz surface and the characterization of the chemical composition and atomic arrangement of the surface. We conclude that there is strong evidence for a hydroxyl group termination appropriate for further chemical reactions. The surface itself is easily accessible, atomically flat and suitable for potential technological applications.
Optical Properties of Irradiated Topaz Crystals
2015
The results of an investigation of UV-Visible absorption and photoluminescence spectra of colorless topaz before and after neutron irradiation, natural blue topaz from Ukraine, and yellow topaz are presented. We assume that the absorption band ~ 620 nm and broad emission band 300-700 nm in topaz crystals are associated with exchange interaction between a radiation defect (anion vacancies, which capture one or two electrons) and impurity ions Cr 3+ , Fe 3+ and Mn 2+ .
Chemical modification of Topaz surfaces
1999
In chemisorption, one is typically faced with the problem that the two-dimensional structure of the organic layer does not match the structure of the inorganic substrate. This work describes the first steps toward an induced epitaxial correlation of organic compounds on an inorganic surface. The idea of this work was to use a single crystal with a two-dimensional surface structure, Topaz (001), that matches an alkyl chain lattice better than existing substrates. X-ray reflectivity and FTIR experiments prove the surface modification of the Topaz, which is probably an etherification of the reactive OH-groups on the Topaz (001) surface.