Rare earth-transition metal glass

Table 11.6 Colours generated by transition-metal and rare earth ions in glass (After Varshneya, 1994).

If all these conditions are met, persistent spectral hole can result. The PSHB phenomenon is quite general and has been observed in many types of inorganic materials, for example, color centers (Macfarlane, 1979, 1983), rare earth ions in crystals (Macfarlane, 1987 Beck, 1998), transition-metal ions in crystals (Moemer, 1988), rare-earth ions in glasses (Macfarlane, 1983 Hirao, 1993), and semiconductor nanometer particles (Masumoto, 1995 Naoe, 1994). 

The colors obtained depend primarily on the oxidation state and coordination number of the coloring ion (3). Table 1 Hsts the solution colors of several ions in glass. AH of these ions are transition metals some rare-earth ions show similar effects. The electronic transitions within the partially filled d andy shells of these ions are of such frequency that they fall in that narrow band of frequencies from 400 to 700 nm, which constitutes the visible spectmm (4). Hence, they are suitable for producing color (qv). 

Moreno M, Aramburu JA, Barriuso MT (2003) Electronic Properties and Bonding in Transition Metal Complexes Influence of Pressure 106 127-152 Morita M, Buddhudu S, Rau D, Murakami S (2004) Photoluminescence and Excitation Energy Transfer of Rare Earth Ions in Nanoporous Xerogel and Sol-Gel SiC>2 Glasses 107 115-143... 

The colors in rare earth glasses are caused by the ion being dissolved and they behave uniquely because the 4 f electrons are deeply buried. Their colors depend on transitions taking place in an inner electronic shell while in other elements such as the transition metals, the chemical forces are restricted to deformation and exchanges of electrons within the outer shell. Since the rare earth s sharp absorption spectra are insensitive to glass composition and oxidation-reduction conditions, it is easy to produce and maintain definite colors in the glass making process. ( )... 

Off-line dicarbamate solvent extraction and ICP-MS analysis [317] provided part-per-trillion detection limits Cd (0.2 ppt), Co (0.3 ppt), Cu (3 ppt), Fe (21 ppt), Ni (2 ppt), Pb (0.5 ppt), and Zn (2 ppt). Off-line matrix removal and preconcentration using cellulose-immobilized ethylenediaminetetraacetic acid (EDTA) have also been reported [318]. Transition metals and rare earth elements were preconcentrated and separated from the matrix using on-line ion chromatography with a NTA chelating resin [319]. Isotope-dilution-based concentration measurement has also been used after matrix separation with a Chelex ion-exchange resin [320]. The pH, flow rate, resin volume, elution volume, and time required for isotope equilibration were optimized. A controlled-pore glass immobilized iminodiacetate based automated on-line matrix separation system has also been described [321]. Recoveries for most metals were between 62% and 113%. 

Inone and his group investigated the aluminum alloys combined with rare earth and transition metals such as the ternary alloys La/Al/Ni or La/Al/Cn. From there, they investigated more complicated alloys and demonstrated that the fabrication of glass samples having a thickness of about 1 cm was possible, for instance, in the alloys La/AFCu/Ni. 

E24.13 BeO, B2O3, and to some extent Ge02 because they involve metalloid and non-metal oxides. Transition metal and rare earth oxides are typically non-glass-forming oxides, many of which have crystalline phases. 

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