Silicate glasses energy levels

The time-resolved spectroscopy of Cr doped spinel and petalite-like phase types glass-ceramics enables a more accurate distinction of the and T2 energy levels of Cr(III) and of the equilibrium between the population of two levels, see Fig. 5, which presents the time-resolved spectra of spinel type glass-ceramics excited at 680 nm at room temperature Glass-ceramics derived from boro-silicate glasses containing Cr(III) were also recently studied by laser spectroscopy and fluorescence-line narrowing. 

Recently Kowada et al. (28-31) explained the optical propoties of silicate glasses based on energy level stmctures calculated using glassy state cluster models. However they have not yet treated the problem of why the optical properties change with metal oxide content (28-31). We think that PDOS as a function of composition can be used... 

Fig. 2. Multiphonon emission rates of rare-earth ions in silicate, fluoride and chlorofluoride glasses. The position of three levels or Er3+ ions are indicated, with respect to the energy gap to the next-lower level (reproduced with permission from Eur. J. Solid State Inorg. Chem., 31 (1994) 337 [44]).

Fig. 3. Dependence of multiphonon relaxation on the number of phonons in the glass former needed to bridge the energy gap between the luminescent /-level and the closest lower-lying level. The curves refer to glasses of the following types (1) phosphate (2) borate (3) silicate (4) tellurite (5) fluoroberyllate (6) germanate (7) zirconium fluoride (ZBLA) (8) aluminum lanthanide sulfide (ALS) and gallium lanthanide sulfide (GLS) (9) the crystalline hosts YjAljOj CYAG), and (10)...

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