Quenching of the Fluorescence from Chromium(III) Ions in Chromium-Doped Forsterite by an Aluminum Codopant

Correlations and zoning patterns of phosphorus and chromium in olivine from H chondrites and the LL chondrite Semarkona

“…; Mass et al. ). Another possibility is the substitution of a pair of Cr 3+ cations with an octahedral vacancy for three octahedral divalent elements: for example, 3 vi M 2+ = 2 vi Cr 3+ + vi □ (Gaister et al.…”

“…The specific substitution mechanism(s) by which this Pindependent Cr is incorporated into chondrule olivine is not known, although there are several possibilities including an indirect association of these cations rather than a direct coupled substitution involving charge balancing (Milman-Barris et al 2008). One potential substitution to incorporate Cr into the olivine structure involves a coupled substitution of octahedral Cr 3+ and tetrahedral Al 3+ substituting for an octahedral divalent element (e.g., Fe 2+ , Mg) and tetrahedral silica: for example, iv Si 4+ + vi M 2+ = iv Al 3+ + vi Cr 3+ (Bershov et al 1983;Colson et al 1989;Mass et al 1995). Another possibility is the substitution of a pair of Cr 3+ cations with an octahedral vacancy for three octahedral divalent elements: for example, 3 vi M 2+ = 2 vi Cr 3+ + vi □ (Gaister et al 2003).…”

Fluorescence Line-Narrowing Study of Eu3+-Doped Sol−Gel Silica: Effect of Modifying Cations on the Clustering of Eu3+

“…Most of the work on lasing has focused on Nd 3+ , or organic dye doping. − Er 3+ up-conversion has also been recently reported in sol−gel silica . The optical absorption and/or luminescence properties of several transition-metal and rare-earth ions incorporated into sol−gel silica have been reported, including Cr 3+ , , Ni 2+ , Fe 3+ , Sm 2+ , Nd 3+ , − Er 3+ , , Yb 3+,34 and Pr 3+ . A number of these ions have also been used as dopants in nonsilicate sol−gel matrices. ,, …”

Crystallization and Spectroscopic Properties of Electron-Beam-Deposited, Chromium-Doped, Forsterite Films

“…Target Material Preparation. A chromium-doped (8 × 10 -5 mol) methanolic solution of magnesium (0.298 mol) and silicon (0.118 mol) methoxides (Mg/Si molar ratio of 2.53 and Cr/Si molar ratio of 6.58 × 10 -4 ) was prepared using chromium trioxide as a chromium source according to the technique previously used for the synthesis of Cr,Al:Mg 2 SiO 4 . The sol was hydrolyzed using the hydrogen peroxide-assisted method that has been developed for the sol−gel synthesis of forsterite and olivine. ,, This method involves the slow addition (via a syringe pump) of a dilute methanolic solution of 30% hydrogen peroxide (sufficient to hydrolyze 75% of the OR groups) to the reaction mixture.…”