Cesium oxides are materials of great interest to the photodetection industry because of their relatively low work function (∼1 eV). Used mainly as coating films for photoemissive devices, they provide high wavelength thresholds and high photocurrents. However, they are unstable, air-sensitive, and hygroscopic, rendering them short-lived and limiting their applications. Although the technology of these devices is highly developed, their characterization on the micro-and nanoscale suffers from their poor chemical stability and poor crystallinity. In the present study, cesium oxides were synthesized from the elements and were characterized using a combination of chemical and structural analysis techniques. Because the reaction products were extremely sensitive to humidity, sample analysis without atmospheric exposure was essential, and techniques were developed for the transfer of the samples to the measurements systems. Extensive data obtained from X-ray energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), selected-area electron diffraction (SAED), X-ray diffraction (XRD), and Raman microscopy were obtained. Raman spectra with bands at 103, 742, and 1134 cm -1 strongly confirmed the presence of the oxide, peroxide, and superoxide ions, respectively, as well as the absence of carbonate as an impurity. The A 1g mode of Cs 2 O was detected as an anti-Stokes band at 103 cm -1 . This study provides further insight into the reactivity of the various cesium oxides.

The Raman spectrum of Cs 2 O 2 excited at 632.8 nm shows a single O 2 −2 fundamental band at wavenumber of 742.5 cm −1 and second and third overtones at 1468.5 and 2176.8 cm −1 , respectively. The harmonic wavenumber ! e = 759.5 ± 0.7 cm −1 and anharmonicity constant ! e x e = 8.4 ± 0.3 cm −1 were calculated directly from the measurements. These results are compared with ! e = 1151.0 ± 1.5 cm −1 and ! e x e = 9.6 ± 0.5 cm −1 recently found for O 2 − ion in CsO 2 by others. The lower ! e x e of O 2 −2 relative to that of O 2 − indicates a broader (smaller curvature) anharmonic oscillator potential well.

Recently, rare earth doped vanadates have been identified as potential successor to YAG crystals. Not much is known about the ionising radiation effect on the lasing and other properties of vanadates. Colour centres, defects, etc. formation by y-ray irradiation in pure and Yb3+ doped YVO4, studied by thermoluminescence measurements, is reported here. It is shown that vanadates are less sensitive to y-ray irradiation. A suitable model for colour centre formation and thermoluminescence emission has been suggested.

E 3+ and ABaGd0.5(PO4)2 :En3.~ (where A+= Li, Na or K) double phosphates Abstract. BaGd0.s(PO4)2 : uo. 5 were synthesized by solid state diffusion method. These powders were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. XRD results showed many distinct lines in the XRD spectra. SEM measurement showed grains of different sizes in double phosphates. The Eu3+-ion emission lines for SD 0-> 7Fj (j = 1, 2, 3, and 4) transitions showed a splitting into 3, 2, 1, and 2 components, respectively. E 3+ double phosphate. Strength of these lines was enhanced by the addition of alkali ion to BaGdo.s(PO4)2 : Uo. 5 However, as the alkali ion varied from Li ÷ to K ÷, the intensity of 5/90-> 7F2 line (617 nm) in the red region increased at the cost of 5D 0-> 7F1 line (599 nm) in the orange region. Suitable explanation has been proposed for this phenomena.

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