Temperature Dependence of the Raman Spectrum of Barium Peroxide

Abstract

The Raman spectra of barium peroxide (BaO 2 ) in the O-O stretching region were studied at various temperatures between 22 and 850°C in both O 2 and He atmospheres. Although only one peroxide stretching band is expected for the crystal symmetry, three Raman bands, which were assigned to peroxide ions in different crystal environments due to the relative locations of oxide impurities, were observed at all temperatures. The temperature dependencies of the Raman frequencies, bandwidths, and the absolute and partial intensities were investigated in detail, and these were explained on the basis of the sample composition and structural changes.

Decomposition of Nitric Oxide over Barium Oxide Supported on Magnesium Oxide. 4. In Situ Raman Characterization of Oxide Phase Transitions and Peroxide Species by 18O-Labeling

“…The starting material, after equilibration at 590 °C in 10% O 2 /He, was characterized by a peak maximum at 829 cm -1 and two shoulders at 820 and 810 cm -1 . This observation confirms the Raman data presented by Haller et al., who reported three components in the Raman band of the peroxide stretching mode of crystalline BaO 2 . The maximum of the band depicted in inset A of Figure shifted to 833 cm -1 with decreasing O 2 partial pressures, and the band broadened in the high-frequency wing.…”

“…According to the assignment of the three components in this Raman band given by Haller et al, the band at 829 cm -1 arises from a pure crystalline form of BaO 2 , while the two shoulders at lower frequencies are due to peroxide ions in BaO 2 in close proximity to Ba 2+ ions that are coordinated to one or two defect O 2- ions in BaO 2 . The combined occurrence of intensity reduction, frequency shift, and broadening can be understood, if all three peroxide species identified in BaO 2 are responding to a comparable extent to a decrease in O 2 pressure.…”

Structural and vibrational properties of hydrothermally grown ZnO2 nanoparticles

“…Others authors have also reported a Raman peak for ZnO 2 nanoparticles located at 840 cm À 1 , which was attributed to the stretching mode of the O-O bond of the peroxo ion (O 2 2 À ) [34]. Analogous Raman active modes have been detected in inorganic peroxide compounds like BaO 2 (838 cm À 1 ) attributed to vibration of the O-O bond [46]. Since the ZnO 2 unit cell has an inversion center the rule of mutual execution applies [47]; then a vibrational mode cannot be both Raman and infrared active.…”

In situ transmission Fourier transform infrared (FT-IR) spectroscopy investigations of the surface chemistry of gettering common gases in vacuum systems with a common commercial flashed getter alloy as a function of temperature

“…This is consistent with XPS results that show the film to be relatively homogenous in concentrations of Ba and Sr but more heterogeneous in concentrations of Ni and Al. Such heterogeneous structure has been observed in commercial BaO materials and yields complex Raman spectra owing to the different crystalline environments [19].…”