Photostimulated luminescence at room temperature was observed in a fluorozirconate glass which was doped with 1% Eu2+ or 1% Ce3+ and 5% Br− ions. Small crystals of BaBr2 (high-pressure phase) form in the glass on cooling. The Eu2+ and Ce3+ luminescence spectra comprised two emission lines each: for Eu2+ one line at 413 nm and a broader band centered at 485 nm, and for Ce3+ one line at 320 nm and a broader band at 425 nm. The luminescence is attributed to the 5d14fn−1→4fn emissions of the rare earth ions. In both cases only one of the emission bands showed photostimulated luminescence. The stimulation band for both rare earth ions was centered at 570 nm.

In spray flame synthesis the processes of spray formation and evaporation of the single droplets greatly affect the morphology and size of particles formed. An in situ measurement of these parameters is thus essential for process control and development. In this work, wide-angle light scattering (WALS) is applied to measure droplet sizes in a spray flame. The scattering data of the spherical droplets are evaluated by applying Mie-theory. For droplet sizing, the number of characteristic maxima in the scattering pattern and the measured scattering intensities are evaluated. Droplet size distributions and their parameters were determined by repetitive exposures in various heights above the nozzle outlet for two solvents: pure ethanol and a mixture of ethanol and 2-ethylhexanoic acid at a volume ratio of 35/65. While for ethanol the median droplet size decreases with increasing height, it decreases less for the mixture, which in general exhibits increased droplet sizes for all heights compared to pure ethanol. Furthermore, we could show that using air instead of nitrogen as a co-flow barely affects droplet evaporation in the flame.

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Structure and photostimulated luminescent properties of Eu-doped M 2 Ba X 4 ( M = Cs , Rb; X = Br , Cl)It was previously shown that RbBr doped with Ga ϩ is an efficient x-ray storage phosphor with a figure of merit comparable to that of the commercially used BaFBr:Eu 2ϩ . The paramagnetic hole centers generated upon x-irradiation involved in the storage and read-out process were investigated by measuring the magnetic circular dichroism of the optical absorption ͑MCDA͒, the MCDA-detected electron paramagnetic resonance ͑MCDA-EPR͒ and the photostimulated luminescence ͑PSL͒. Two different Ga 2ϩ hole centers with a hyperfine interaction with 69 Ga of 69 Aϭ8.2 GHz and 69 Aϭ6.0 GHz, respectively, were found. No superhyperfine interaction was resolved. Therefore, the structural difference between the two Ga 2ϩ centers could not be established from EPR. The PSL effect is correlated only to one of the two Ga 2ϩ centers, namely that with Aϭ8.2 GHz. The generation mechanism of the two hole centers is investigated. It is proposed that the PSL-active Ga 2ϩ center is an isolated Ga 2ϩ on a Rb ϩ site, whereas the other center is a Ga 2ϩ -cation vacancy complex.

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