Compositional Dependence of Optical Absorption in Barium Oxychloride Borate Glasses

2017 ◽  
Vol 6 (1) ◽  
pp. 116-120 ◽  
Author(s):  
M. S. Dahiya ◽  
A. Agarwal ◽  
S. Khasa
Keyword(s):  
Optical Absorption ◽  
Behavioral Change ◽  
Structural Changes ◽  
Optical Band Gap ◽  
Compositional Dependence ◽  
Absorption Data ◽  
Optical Band Gaps ◽  
Mott Model ◽  
Urbach’S Energy ◽  
Absorption Tail

The present communication deals with some significant results pertaining to the optical absorption analysis of glasses in the compositional range of xBaCl2·(30–x)·BaO·68B2O3·2V2O5 (x = 0, 5, 7 and 10 mol%) prepared via convenient melt-quench route. The optical absorption data recorded in wavelength range of 200–800 nm is analyzed by means of Davis-Mott model to evaluate optical band gaps corresponding to direct and indirect transitions. The absorption tail is analyzed to obtain Urbach's energy. Behavioral change in optical band gap and Urbach's energy with changing chlorine concentrations is discussed to predict the structural changes governed in the glass matrix.

scholarly journals Physical, Optical, and Spectroscopic Studies on MgO-BaO-B2O3 Glasses

ISRN Ceramics ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Samdani ◽  
Md. Shareefuddin ◽  
G. Ramadevudu ◽  
S. Laxmi Srinivasa Rao ◽  
M. Narasimha Chary
Keyword(s):  
Optical Absorption ◽  
Urbach Energy ◽  
Glass Composition ◽  
Glass Network ◽  
Spectroscopic Studies ◽  
Band Gaps ◽  
Compositional Dependence ◽  
Paramagnetic Resonance ◽  
Optical Band Gaps ◽  
Electron Paramagnetic

The mixed alkaline effect in double alkaline borate glasses MgO-BaO-B2O3 containing small proportions of copper oxide (CuO) has been studied. The glass samples are characterized by optical absorption, electron paramagnetic resonance (EPR), and Fourier transform infrared spectroscopy (FTIR). A red shift in optical absorption peaks with increasing MgO (decreasing BaO) concentration has been observed. The values of “g” tensor and hyperfine “A” tensor have shown inflections with glass composition. The number of spins (N) and paramagnetic susceptibility (χ) also exhibited mixed alkaline effect. The broadening of glass network with increase in MgO concentration is found from the FTIR spectra. Interestingly both density and molar volume have shown decreasing trend with glass composition. The optical band gaps exhibited a nonlinear compositional dependence. As expected, the glass samples possessed higher values of optical basicity (Λ), molar electronic polarizability (αm), and Urbach energy (ΔE).

SYNTHESIS AND SPECTROSCOPY OF SOME QUATERNARY OXYFLUORIDE GLASSES DOPPED WITH COPPER

2013 ◽  
Vol 22 ◽  
pp. 284-291 ◽  
Author(s):  
CH. SRINIVASU ◽  
M. A. SAMI ◽  
A. EDUKONDALU ◽  
SYED RAHMAN
Keyword(s):  
Optical Absorption ◽  
Absorption Spectra ◽  
Copper Ions ◽  
Wave Length ◽  
Broad Band ◽  
Spin Hamiltonian Parameter ◽  
Band Gap Energy ◽  
Site Symmetry ◽  
Optical Absorption Spectra ◽  
Absorption Data

Electron paramagnetic resonance (EPR) and optical absorption spectra of copper ions in xLiF-(50-x)Li2O-20SrO-30Bi2O3 glass system have been studied. MDSC studies showed that the glass transition temperature decreases with LiF content. Optical absorption spectra of the pure glasses reveled that the cut off wave length increased and optical band gap energy decreased with increase in LiF content. EPR spectra of all the glass samples exhibit resonance signals characteristic of Cu2+ ions. The Cu2+ ions are in well-defined axial sites but subjected to small distortion leading to the broadening of the spectra. The spin-Hamiltonian parameter values indicate that the ground state of Cu2+ is d x2 y2 and the site symmetry around Cu2+ ions is tetragonally distorted octahedral. The optical absorption spectra exhibited a broad band corresponding to the d-d transition bands of Cu2+ ion. By correlating EPR and optical absorption data, the bond parameters are evaluated from various techniques.

scholarly journals Structural and spectroscopic analyses of copper doped P2O5-ZnO-K2O-Bi2O3 glasses

2015 ◽  
Vol 9 (3) ◽  
pp. 169-173 ◽  
Author(s):  
Yahia Elbashar
Keyword(s):  
Optical Band Gap ◽  
Band Gap Energy ◽  
Dielectric Constants ◽  
X Ray Diffraction ◽  
Band Tail ◽  
Absorption Data ◽  
X Ray ◽  
Spectroscopic Analyses ◽  
Acceptable Range ◽  
Prepared Glass

Homogeneous glass samples with different compositions 42(P2O5)?40 (ZnO)?(16?x)(K2O)?2 (Bi2O3)?x(Cu2O) (where x = 1, 2 and 3mol%) were prepared by conventional melt-quenched technique under controlled conditions. The structure of the prepared glass samples was investigated by X-ray diffraction. Optical properties (transmittance and reflectance) of the glasses were measured in the wavelength range 200-900 nm. The optical band gap energy of the investigated glasses with 1, 2 and 3mol% Cu2O was estimated from absorption data using the Mott and Davis relation and found to be 2.33, 2.45 and 2.53 eV, respectively. The mechanism of optical absorption was found to be direct. The band tail width was also estimated and found to lay in the acceptable range. Refractive index, absorption coefficient, extinction coefficient and real/imaginary parts of dielectric constants were calculated. Further to this, some theoretical investigation of the spectral problems was carried out. The investigation was based on finite difference method.

Spectroscopic studies of the interaction of cationic water-soluble iron(III) meso-tetrakis(4-N-methylpyridiniumyl)porphyrin (FeTMPyP) with ionic and nonionic micelles

2005 ◽  
Vol 09 (02) ◽  
pp. 94-108 ◽  
Author(s):  
Patrícia S. Santiago ◽  
Shirley C. M. Gandini ◽  
Marcel Tabak
Keyword(s):  
Optical Absorption ◽  
Binding Constants ◽  
Spectroscopic Studies ◽  
Resonance Light Scattering ◽  
Water Soluble ◽  
Absorption Data ◽  
Additional Species ◽  
Surfactant Aggregates ◽  
Order Of Magnitude ◽  
Triton X

Interactions of cationic FeTMPyP with ionic and nonionic micelles have been studied by optical absorption, resonance light scattering (RLS) and 1 H NMR spectroscopies. The equilibrium behavior of FeTMPyP as a function of pH is described by several species in aqueous solution. The presence of phosphate anions leads to the existence of additional species in the acid p H region, probably due to the coordination of phosphates to the iron. FeTMPyP solution as a function of pH in the presence of anionic SDS showed a simplified equilibrium in acidic pH region, favoring the transition to the dimeric species. Titration of FeTMPyP as a function of SDS surfactant concentration showed the presence of three different porphyrin species: free metalloporphyrin monomers (or dimers depending on pH), metalloporphyrin monomers (or dimers) bound to the micelles, and nonmicellar metalloporphyrin/surfactant aggregates. In the case of zwitterionic LPC and HPS, and nonionic TRITON X-100 the nonmicellar metalloporphyrin/surfactant aggregates were not observed. Binding constants were calculated from optical absorption data and have values of 2 × 103 M −1 for SDS being much smaller for HPS (58 M −1), LPC and TRITON X-100. Comparison with our previous data for anionic FeTPPS 4 shows that both the electrostatic factor and hydrophobic forces are relevant in the porphyrin-surfactant interaction: for FeTPPS 4 binding constants to cationic CTAC and zwitterionic HPS are of the same order of magnitude, 1-3 × 104 M −1; for FeTMPyP the delocalization of the positive charges from the periphery substituents into the macrocycle ring leads to reduction of both electrostatic attraction to the micelle as well as hydrophobic character of the porphyrin ring, leading to a 10-fold reduction of binding to the micelles of opposite charge to the porphyrin. NMR data indicated that FeTMPyP is bound to the micelles as an equilibrium of two forms of monomer at pH 2.0, and at pH 9.0 the bound aggregated form (possibly dimers) is observed predominantly with some amount of a monomeric form.

scholarly journals Effects of the Argon Pressure on the Optical Band Gap of Zinc Oxide Thin Films Grown by Nonreactive RF Sputtering

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
M. Acosta ◽  
I. Riech ◽  
E. Martín-Tovar
Keyword(s):  
Thin Films ◽  
Zinc Oxide ◽  
Band Gap ◽  
Room Temperature ◽  
Optical Band Gap ◽  
Rf Sputtering ◽  
Argon Pressure ◽  
Band Gaps ◽  
Zno Thin Films ◽  
Optical Band Gaps

Zinc oxide (ZnO) thin films were grown by nonreactive RF sputtering at room temperature under varying argon pressures (PAr). Their optical band gap was found to increase from 3.58 to 4.34 eV when the argon pressure increases from 2.67 to 10.66 Pa. After annealing at 200°C and 500°C, optical band gaps decrease considerably. The observed widening of the band gap with increasingPArcan be understood as being a consequence of the poorer crystallinity of films grown at higher pressures. Measurements of morphological and electrical properties of these films correlate well with this picture. Our main aim is to understand the effects ofPAron several physical properties of the films, and most importantly on its optical band gap.

The characterization of pure and niobium-doped crystals of strontium titanate using Hall, electrical conductivity, and optical absorption data

1978 ◽  
Vol 56 (4) ◽  
pp. 453-467 ◽  
Author(s):  
G. Perluzzo ◽  
J. Destry
Keyword(s):  
Heat Treatment ◽  
Electrical Conductivity ◽  
Optical Absorption ◽  
Hall Effect ◽  
Strontium Titanate ◽  
Defect States ◽  
Absorption Data ◽  
Niobium Doped ◽  
Hall Effect Measurements

A description is given of the heat treatment, under controlled conditions, of crystals of strontium titanate, both pure and niobium-doped, and of the effect of this treatment on the defect states in this material. Our analysis is based on evaluation of the results of electrical conductivity and Hall effect measurements, and those of optical absorption.

Silver Nanocluster Formation In Implanted Silica

1997 ◽  
Vol 504 ◽  
Author(s):  
G. Mariotto ◽  
F. L Freire
Keyword(s):  
Optical Absorption ◽  
Raman Scattering ◽  
Rutherford Backscattering Spectrometry ◽  
Broad Band ◽  
Spherical Shape ◽  
Fused Silica ◽  
Silver Nanoclusters ◽  
Absorption Data ◽  
Broad Absorption Band ◽  
Silver Nanocluster

ABSTRACTSamples of fused silica were implanted at room temperature with 300 keV-Ag+ for doses ranging from 0.8×1016 to 14×1016 ions/cm2. A multi-technique approach including Rutherford backscattering spectrometry (RBS), x-ray diffraction (XRD), optical absorption and Raman scattering spectroscopies has been used to characterize silver precipitate. The Ag-depth profiles of samples implanted with doses higher than 6×1016 Ag+/cm2 show a bi-modal distribution, with the appearance of a secondary maximum near the surface. XRD spectra indicated the formation of silver nanocrystals of ∼10 nm in size within the heavily implanted samples. Optical absorption has been used to monitor the effects of ion doses on the optical properties of the metal clusters in the UV-Vis region. A single broad absorption band, due to surface plasmon resonance, is peaked at about 400 nm for low implantation doses. For doses higher than 4.3×1016 Ag+/cm2, a second broad band originates at higher wavelengths, peaking at 625 nm for the highest dose. The evolution of optical spectra is tentatively discussed in terms of the formation of silver particle aggregates with no longer spherical shape. An estimate of the mean size of silver nanoclusters of about 5.5 nm is obtained from low-frequency Raman scattering due to acoustic vibrations localized at the cluster surface. The discrepancies in the metal particle size obtained from XRD and Raman scattering measurements are discussed with respect to optical absorption data.

scholarly journals Quick-EXAFS setup at the SuperXAS beamline forin situX-ray absorption spectroscopy with 10 ms time resolution

2016 ◽  
Vol 23 (1) ◽  
pp. 260-266 ◽  
Author(s):  
Oliver Müller ◽  
Maarten Nachtegaal ◽  
Justus Just ◽  
Dirk Lützenkirchen-Hecht ◽  
Ronald Frahm
Keyword(s):  
Absorption Spectra ◽  
Absorption Spectroscopy ◽  
Time Resolution ◽  
Structural Changes ◽  
Oscillation Period ◽  
Low Noise ◽  
Bragg Angle ◽  
Absorption Data ◽  
Quick Exafs ◽  
Paul Scherrer

The quick-EXAFS (QEXAFS) method adds time resolution to X-ray absorption spectroscopy (XAS) and allows dynamic structural changes to be followed. A completely new QEXAFS setup consisting of monochromator, detectors and data acquisition system is presented, as installed at the SuperXAS bending-magnet beamline at the Swiss Light Source (Paul Scherrer Institute, Switzerland). The monochromator uses Si(111) and Si(311) channel-cut crystals mounted on one crystal stage, and remote exchange allows an energy range from 4.0 keV to 32 keV to be covered. The spectral scan range can be electronically adjusted up to several keV to cover multiple absorption edges in one scan. The determination of the Bragg angle close to the position of the crystals allows high-accuracy measurements. Absorption spectra can be acquired with fast gridded ionization chambers at oscillation frequencies of up to 50 Hz resulting in a time resolution of 10 ms, using both scan directions of each oscillation period. The carefully developed low-noise detector system yields high-quality absorption data. The unique setup allows both state-of-the-art QEXAFS and stable step-scan operation without the need to exchange whole monochromators. The long-term stability of the Bragg angle was investigated and absorption spectra of reference materials as well as of a fast chemical reaction demonstrate the overall capabilities of the new setup.

Studies of Intersubband Transitions in Arrays of Bi Nanowire Samples Using Optical Transmission

2001 ◽  
Vol 707 ◽  
Author(s):  
M.R. Black ◽  
K. R. Maskaly ◽  
O. Rabin ◽  
Y. M. Lin ◽  
S. B. Cronin ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Quantum Confinement ◽  
Optical Transmission ◽  
Large Diameter ◽  
Surface Effects ◽  
Intersubband Transitions ◽  
Absorption Data ◽  
Future Directions ◽  
Wire Arrays ◽  
Bi Nanowire

ABSTRACTThis paper reports the fabrication of large diameter pores (> 150nm) in anodic alumina that can be used to create wire arrays with significant surface effects, but without significant quantum confinement. These wires, therefore, allow us to distinguish between optical absorption spectra features originationg from quantum effects and those from surface effects. The paper presents techniques towards fabrication these bismuth wire arrays, and presents optical absorption data from two bismuth namowire arrays in the semimetal-semiconductor transition diameter regime. The results from previous publications are summarized and future directions are outlined.

scholarly journals Compositional dependence of optical band gap and refractive index in lead and bismuth borate glasses

2015 ◽  
Vol 68 ◽  
pp. 27-34 ◽  
Author(s):  
Saisudha B. Mallur ◽  
Tyler Czarnecki ◽  
Ashish Adhikari ◽  
Panakkattu K. Babu
Keyword(s):  
Refractive Index ◽  
Band Gap ◽  
Optical Band Gap ◽  
Borate Glasses ◽  
Compositional Dependence ◽  
Bismuth Borate
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