Samarium ions (Sm2+) incorporated into aluminosilicate glasses by a sol‐gel process showed persistent spectral hole burning at room temperature. Gels of the system Na2O‐Al2O3SiO2 synthesized by the hydrolysis of Si(OC2H5)4, Al(OC4H9)3, CH3 COONa, and SmCl3·6H2O were heated in air at 500°C, then reacted with H2 gas to form Sm2+ ions. Whereas Al3+ ions effectively dispersed the Sm3+ ions in the glass structure, Na+ ions were not effective. The Al2O3‐SiO2 glasses proved appropriate for reacting the Sm3+ ions with H2 gas and exhibited the intense photoluminescence of Sm2+ ions. The reaction of Sm3+ ions with H2 in the Al2O2‐SiO2 glasses was determined by first‐order kinetics, and the activation energy equaled 95 kJ/mol. At 800°C, the maximum photoluminescence of the Sm2+ ions was achieved within 20 min.

Formation of Sm2+ Ions in Sol-Gel Derived Glasses of the SystemNa2O-Al2O3-SiO2.-Sm2+-doped title glasses are prepared by sol-gel processing at 500 . degree.C in air and reduction of the Sm3+ ions in the resulting glass at 400-900 • C by H2. The conversion of Sm3+ to Sm2+ is studied by optical absorption and photoluminescence measurements. The reaction of Sm3+ with H2 which is determined by first-order kinetics is favored by addition of Al3+ ions. -(NOGAMI, M.; HAYAKAWA, N.; SUGIOKA, N.; ABE, Y.; J.

An instrumental technique for DAFS measurements which can provide site-specific information is proposed. The approach uses (i) focusing optics with parabolic mirrors and a double-crystal monochromator, (ii) the Laue and Bragg settings and (iii) data collection by the image-plate Weissenberg method. Six image exposures are recorded per plate at five intrinsic energies and one reference energy. The single-crystal measurements were performed at the Co K-absorption edge, and the 200, 220 and 311 reflections of CoO and 511 and 911 reflections of Co(3)O(4) were used for analysis. The regression analysis of chi(k), Fourier transforms of k(3)chi(k) and back-Fourier filtering have been performed.