Ions In Phosphate Glasses Research Articles

Valence instability of samarium ions in phosphate glasses

Ultrasonic wave velocity, Raman spectra and electrical measurements have been made in samarium phosphate glasses. Both the bulk and the shear moduli decrease under hydrostatic pressure: these glasses show the extraordinary property of becoming easier to compress as pressure is increased. This is in marked contrast to the normal behaviour under pressure of other phosphate glasses. Raman spectroscopy shows that the structures of the samarium phosphate glasses are similar to those of other phosphate glasses. The unusual pressure-induced behaviour is consistent with valence instability of the samarium ions. The temperature dependence of the electrical conductivity is consistent with the small polaron mechanism.

The local symmetry of Cu 2+ ions in phosphate glasses

The x CuO(1 − x ) [2P 2 O 5 ·Na 2 O] glasses have been investigated by ESR method. The characteristic parameters: g ∥ = 2.426, g ⊥ = 2.089, A ∥ = 119×10 −4 cm −1 and A ⊥ = 21 × 10 −4 cm −1 were attributed to Cu 2+ ion in an unusual tetrahedral (T d ) configuration. It has also been estimated that an admixture of ⋍ 5% of the 4p z (Cu) orbital in the 3d xy ground state of the paramagnetic electron exists.

Electron paramagnetic resonance of Cu2+ and VO2+ ions in phosphate glasses

Electron spin resonance (ESR) spectra ofx(CuO · V2O5 (1 −x) (Na2O · P2O5) andx(CuO · 2V2O5) (1 −x) (Na2O · P2O5) glasses for 0 ⩽x ⩽ 40 have been studied at the X-band and at 300 K. It is found that forx ⩽ 5, both Cu2+ and VO2+ are present, mostly as isolated species. Forx ⩾ 10, broad resonance lines atg = 2.1524 forx(CuO · V2O5) (1 −x) (Na2O · P2O5) and atg = 2.1448 forx(CuO · 2V2O5) (1 −x) (Na2O · P2O5) are observed which may be mainly due to dipole-dipole type interaction between transition metal (TM) ions. Spin Hamiltonian parameters of TM ions have been calculated. Optical spectra of the sodium phosphate glasses doped with single TM ions have also been studied. The theoretical optical basicity, Ath, of these doped glasses has been calculated. It is found that for VO2+ ionsg‖,g⊥ and κ increase whileA‖,P and Δg|/Δg⊥ decrease with increase in Ath. However, no significant change is observed in the spin Hamiltonian parameters of Cu2+ with the change in Ath.

Luminescence of Cu + ions in phosphate glass

Time-resolved fluorescence and lifetime measurements of Cu + ions in phosphate glass with different copper concentrations have been performed at room temperature and 77 K. The experimental results are explained by energy transfer.

Electron spin resonance in phosphate glasses containing mixed transition metal ions

Phosphate glasses containing mixed Cu2+/Ni2+ and Cu2+/Co2+ oxides have been examined. A pronounced decrease in the optical absorption at 830 nm due to the Cu2+ ions is observed as the CuO in the glasses is gradually replaced by NiO or CoO and the decrease is accompanied by a pronounced decrease in the strength of the electron spin resonance (ESR) signal at 9.52 GHz. By combining the ESR and optical absorption data it is concluded that the decrease in concentration of Cu2+ ions in phosphate glasses may be due to an oxidation-reduction mechanism between two valency states of the two different transition metals, of the form Cu2++Ni+→Cu++Ni2+ and Cu2++Co+→Cu++Co2+.

Paramagnetic resonance study on transition metal ions in phosphate, fluorophosphate and fluoride glasses, part I: Cr 3+ and Mo 3+

The ESR of Cr 3+ in phosphate, fluorophosphate and fluoride glasses has been studied. The energy level splitting and the effective g value of the Cr 3+ ion have been calculated with the spin-Hamiltonian. It is pointed out that the transition can be found not only within every Kramers doublet, but also between two Kramers doublets. The zero field splitting parameters D has been determined: 0.15–0.4 cm −1. In this paper, the ESR of the Mo 3+ ion in phosphate glass is also reported.

Investigation of the mechanisms of interaction between chromium and neodymium ions in phosphate glasses

Mechanisms of the Cr Nd excitation energy transfer in Li–La1–x–y –Ndx–Cry phosphate glasses were studied. It was established that the interaction between chromium and neodymium ions is of the dipole-dipole nature. It was found that at T = 77 °K the transfer of energy from chromium to neodymium ions is purely static and it is accelerated by energy migration between chromium ions when the temperature is increased to room temperature. Energy transfer from neodymium to chromium ions is due to the static mechanism and also due to hopping quenching under conditions of migration between neodymium ions. In a narrow temperature range near 150 °K, a regime involving supermigration quenching of neodymium luminescence by chromium ions is established. The microparameters of the elementary interactions between the active particles were determined. It was established that for concentrations x = 0.3 and y = 0.03, reverse transfer from neodymium to chromium ions is negligible at room temperature.

Some bonding aspects of cobalt ions in phosphate glasses

Phosphate glasses containing different concentrations of CoO, Na 2O and CaO were prepared. Their visible, near IR spectra and paramagnetic moments were measured. The results indicated that in all the glasses studied, cobalt existed in the +2 formal oxidation state. The microsymmetry of the cobalt complex species (Co 2+ surrounded by oxygens) was found to change from octahedral, O h , at low metal oxide concentrations to tetrahedral, T d , at high oxide concentrations. There is evidence that the change takes place via the formation of an 8-coordinated species that has common symmetry elements with each of the O h and T d symmetries. The covalent character of the CoO bond was found to increase with the increase in the metal oxide concentration indicating an increase in the CoO orbital overlap.

Luminescence of uranyl ions in phosphate glass and phosphoric acid, spontaneous reduction to uranium(IV) and new description of the electron transfer bands

The absorption and emission spectra of the uranyl ion in phosphate glass and in 85 percent phosphoric acid are similar to the dilute aqueous solution, but the luminescence yield is far higher and small concentrations of uranium(IV) occur, possibly as a quasistationary equilibrium with free oxygen. The quantum numbers Ω of the excited states are discussed, based on “weak-field” coupling between 2F 1 2 and ω = 3 2 or 1 2 of π u. Detailed viriations of band positions are related to UO bond length modification, also in borate and germanate glasses. The excited uranyl ion may perform energy transfer to lanthanides, conceivably applicable to lasers.

Structure and properties of silver phosphate glasses — Infrared and visible spectra

The infrared and visible spectra of glasses in the Ag 2OP 2O 5 glass-forming system were obtained. The infrared data were interpreted as indicating the presence of polymeric chains in these glasses. The partial covalent nature of the AgOP bond was discussed. A mixed NaPO 3AgPO 3 glass showed no unexpected bands in the infrared spectrum, again showing that silver is behaving in a manner similar to alkali metal ions in phosphate glasses. The shift in the absorption edge in the visible spectra of glasses of different Ag/P ratio was shown to arise from either an increase in the concentration of nonbridging oxygens with increasing silver content, or the presence of colloidal silver metal particles.

ESR of Exchange Coupled Cr3+ Ions in Phosphate Glass

A study of the ESR spectrum of a phosphate glass heavily doped with Cr2O3 is reported. The spectrum is attributed to exchange coupled Cr3+ ion pairs and is interpreted with reference to a spin Hamiltonian containing isotropic exchange, Zeeman, and fine structure terms. From the temperature dependence of the ESR intensity, it is inferred that the coupling is antiferromagnetic with an average coupling constant J=24±2 cm−1. The effects of fine structure interactions on the lineshape and breadth of the glass spectrum are considered, and the magnitudes of the fine structure parameters are estimated from the observed linewidths and dependence of the lineshape on microwave frequency. It is found that the fine structure constants are distributed in the range from 0.03 to 0.3 cm−1. The majority of the pairs are characterized by values near the lower end of the range, but the higher values are required to account for the absorption in the wings of the line.

Effect of irradiation temperature on the radiative yield of Mn3+ ions in phosphate glasses

Effect of irradiation temperature on the radiative yield of Mn3+ ions in phosphate glasses

Use of Thallium(I), Lead(II), and Bismuth(III) as Spectroscopic Probes for Ionic–Covalent Interaction in Glasses

Ultraviolet spectra of thallium(I), lead(II), and bismuth(III) in chloride–sulfate and all-sulfate glasses have been studied, and it is observed that the P13 ← 1S0 transition undergoes a blue shift as the sulfate: chloride ratio increases. This is interpreted in terms of increased ionicity of the probe metal ions in the all-sulfate glass. Spectral data indicate comparable ionicity of the probe metal ions in phosphate glass, but more covalent interactions in silicate glass. It is suggested that the study of these spectral bands may be applied to the problems of oxide ion activity in glasses and of covalency in molten salt chemistry.

Absorption Spectra of First Row Transition Metal Ions in Phosphate Glasses

Journal of the American Ceramic SocietyVolume 52, Issue 1 p. 52-52 Absorption Spectra of First Row Transition Metal Ions in Phosphate Glasses J. C. HADDON, J. C. HADDONSearch for more papers by this authorE. A. ROGERS, E. A. ROGERSSearch for more papers by this authorD. J. WILLIAMS, D. J. WILLIAMSSearch for more papers by this author J. C. HADDON, J. C. HADDONSearch for more papers by this authorE. A. ROGERS, E. A. ROGERSSearch for more papers by this authorD. J. WILLIAMS, D. J. WILLIAMSSearch for more papers by this author First published: January 1969 https://doi.org/10.1111/j.1151-2916.1969.tb12661.xCitations: 38 The writers are at the School of Chemistry, University of Bradford, Bradford 7, England. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume52, Issue1January 1969Pages 52-52 RelatedInformation