Raman scattering study of bulk and nanocrystalline PbMoO4 at high pressures

Abstract

Effect of Li+ ions on enhancement of near-infrared upconversion emission in Y2O3:Tm3+/Yb3+ nanocrystals J. Appl. Phys. 112, 094701 (2012) Long range coupling between defect centres in inorganic nanostructures: Valence alternation pairs in nanoscale silica J. Chem. Phys. 137, 154313 (2012) Pressure dependence of the Verwey transition in magnetite: An infrared spectroscopic point of view J. Appl. Phys. 112, 073524 (2012) Silver nanoisland enhanced Raman interaction in graphene Appl. Phys. Lett. 101, 153113 (2012) Chemical pressure effect on optical properties in multiferroic bulk BiFeO3 J. Appl. Phys. 112, 073516 (2012) Additional information on J. Appl. Phys. High-pressure Raman scattering measurements have been performed in wulfenite (PbMoO 4 ) for both bulk and nanocrystalline powders up to 22 GPa. Our Raman scattering measurements evidence the phase transition from the tetragonal scheelite structure to the monoclinic M-fergusonite structure in both bulk and nanocrystalline powders above 10.8 and 13.4 GPa, respectively. The pressure dependences of the Raman active modes in both structures were compared and discussed based on our theoretical results obtained from lattice dynamics ab initio calculations. V C 2012 American Institute of Physics.[http://dx

Thermally modified molybdenum oxide as a potential sorbent for the removal of metal cations from aqueous solutions

“…5E g . From these, we observe 11 modes in the Raman spectrum of PbMoO 4 single crystal due to accidental degeneracy of the A g and the B g modes at 318 cm -1 and the lower than the measured region frequency of the E g mode (*60 cm -1 ) [66]. The frequencies of the observed Raman peaks are in excellent agreement to those earlier reported in the literature [27,[65][66][67].…”

“…From these, we observe 11 modes in the Raman spectrum of PbMoO 4 single crystal due to accidental degeneracy of the A g and the B g modes at 318 cm -1 and the lower than the measured region frequency of the E g mode (*60 cm -1 ) [66]. The frequencies of the observed Raman peaks are in excellent agreement to those earlier reported in the literature [27,[65][66][67]. Similarly to the XRD measurements, Pb-sorption onto the AHM-derived MoO 3 causes the appearance of additional Raman peaks to those originating from MoO 3 , which is attributed to the formation of Wulfenite PbMoO 4 .…”

Variable-Temperature and High-Pressure Micro-Raman Spectra of Inorganic Artists' Pigments: CrystallineWulfenite, Lead(II) Molybdate(VI), PbMoO4

“…This observation is fully in accord with the latest high-pressure Raman work on both bulk and nanocrystalline PbMoO 4 during which a reversible second-order phase transition was only observed at much higher pressures, namely, 10.8 and 13.4 GPa, respectively. [2] These authors also reported ab initio calculated and experimental wavenumbers and pressure dependences for all 13 Raman-active modes. For the two a g modes indicated above, they obtained the following results (dn=dP values in parentheses):…”

“…[5] We observed seven clearly distinct modes in the 900-100 cm À1 region that match quite well with the literature and calculated values (see also Table 1). [2,5,12] Subsequently, we undertook variable-temperature Raman measurements at 50 C intervals from room temperature up to 600 C. All the peaks red shifted to lower wavenumbers and were broadened with increasing temperature (Fig. 2).…”

“…The PbMoO 4 compound has also attracted considerable attention industrially because of its acousto-optical, photoconductive, luminescent, photocatalytic, and thermoluminescent properties. [2,3] Analyses of the spectroscopic properties of lead chromate and lead molybdate are crucial in understanding the behavior of orange molybdate with respect to dramatic changes in the external temperature and pressure.…”