Infrared, ESR and optical absorption studies of Cu²⁺ ions doped in TeO₂-ZnO-NaF glass system

709-715Glasses of composition 80TeO2-(20−x)ZnO-xNaF mol % were prepared by melt quenching technique and characterized by ESR, optical absorption and infrared spectroscopy. The IR spectra reveal that the glass consists of TeO3, TeO4, Te(O,F)3 and Te(O,F)4 units as local structure of the glass network. The hydroxyl group concentration decreases with the increase of NaF content. From ESR spectra, it is found that the Cu2+ ions are in octahedral sites with tetragonal distortion with as ground state. From the ESR and optical absorption studies, molecular orbital coefficients were calculated and correlated with the structural variation of the glass system. From the optical absorption data, the optical band gap (Eopt) and Urbatch energy (ΔE) values were calculated. It is found that Eopt values increase with NaF content. The low ΔE values showed that the present glasses were highly homogenous and stable

ESR, infrared and optical absorption studies of Cu²⁺ ion doped in 60B₂O₃-10TeO₂-(30-<i style="">x</i>)MO-<i style="">x</i>PbO (M = Zn, Cd) glasses

551-556 ESR, IR and optical absorption studies on 60B2O3-10TeO2-(30-x)MO-xPbO (where M=Zn, Cd) glasses containing Cu2+ spin probe have been carried out. The IR results prove the distribution of trigonal bipyramids (TeO3) which determines the network and the distribution of borate triangles (BO3) and borate tetrahedral (BO4) groups. Structural changes take place with variation of PbO content in BTZP and BTCP series. ESR results show that the g|| > g⊥ indicating that the Cu2+ ion is in tetragonal distorted octahedral site and its ground state is . There are considerable changes in g||, g⊥ and A|| values with the increasing concentration of PbO in both BTZP and BTCP glass systems. The optical absorption spectra results show that the absorption peak of Cu2+ is a function of composition. The observed optical absorption peak of Cu2+ has been found to be maximum at 813 nm for x=30 mol% of PbO content. Bonding parameters are calculated from both optical and ESR data. All these variations clearly indicate the structural changes in the present glass systems with varying PbO content. </smarttagtype

ESR, IR, Raman and optical absorption studies of 60 B2O3 + 10 TeO2 +5TiO2 +24 R2O: 1CuO (where R=Li, Na, K) quaternary glasses

163-169ESR, IR, Raman and optical absorption spectra of 60 B2O3 + 10 TeO2 +5TiO2+24 R2O (where R = Li, Na and K) quaternary glasses containing Cu2+ spin probe have been studied. IR results show the BO3-BO4- ring structure interconnected by TeO3- and TeO4- groups, where the BO4- groups are neighbours of the TeO3-groups. BO3 → BO4 transition is also observed, which correlates with the conversion of TeO4 →TeO3. From Raman spectra, a weak band recorded at 805 cm-1 clearly indicates the presence of boroxol rings for potassium boro-tellurite glass alone. From ESR spectra, the three weak parallel components are observed in the low field region. However, the perpendicular components are not resolved leading to an intensive line in the high field region. When one kind of alkali oxide is replaced by another, the Spin Hamiltonian parameters have been found to vary drastically. The spin Hamiltonian parameter values indicate that the ground state of Cu2+ is dx2- y2 and the site symmetry around the Cu2+ ion is tetragonally distorted octahedral coordination. Optical absorption peak of Cu2+ is found to be a maximum at around 794 nm for Li2O containing borate rich glasses. This peak shifts towards the lower wavelength side as Li2O is replaced with Na2O, K2O. Bonding parameters indicate a slight covalency for the in-plane σ bonding as compared to in-plane and out-of-plane π bonds

Brainhack: Developing a culture of open, inclusive, community-driven neuroscience

Brainhack is an innovative meeting format that promotes scientific collaboration and education in an open, inclusive environment. This NeuroView describes the myriad benefits for participants and the research community and how Brainhacks complement conventional formats to augment scientific progress

Brainhack: Developing a culture of open, inclusive, community-driven neuroscience

Brainhack is an innovative meeting format that promotes scientific collaboration and education in an open, inclusive environment. This NeuroView describes the myriad benefits for participants and the research community and how Brainhacks complement conventional formats to augment scientific progress