Bonding Parameter Values Research Articles

Impact of BaF2 on physical and spectroscopic studies of TeO2–Li2B4O7 glasses modified with Cu2+ ions

The present manuscript deals with the preparation and structural studies of BaF2–TeO2 – Li2B4O7–CuO glasses. The glasses were made using the melt quenching procedure, and their properties were examined utilizing the density, absorption, FTIR, Raman, and EPR spectra. The lack of strong peaks in the XRD spectra provides evidence that the phase is non-crystalline. The samples' densities went up but their molar volumes went down. The transition between 2B1g and 2B2g is responsible for a broad absorption band in optical absorption spectra. With BaF2, the band gap values obtained from the Tauc plot were raised. The density and optical data were used to determine a number of additional characteristics. The existence of various structural groups in the glass structure was shown by the FTIR and Raman spectra. Calculated from EPR spectra, the spin- Hamiltonian and bonding parameter values explained the ligand field around the Cu2+ ions.

Enhanced luminescence properties and Judd-Ofelt analysis of novel red emitting Sr2LiScB4O10: Eu3+ phosphors for WLED applications

In this work, a new series of red emitting Eu 3+ ions activated Sr 2 LiScB 4 O 10 phosphors were synthesized by a traditional high temperature solid-state reaction technique and their structural and luminescence behavior were studied through analyzing X-ray diffraction, Scanning electron microscopy, Fourier transform infrared spectroscopy, optical absorption, photoluminescence as well as decay spectral measurements, respectively. XRD pattern showed that the prepared Sr 2 LiScB 4 O 10 :Eu 3+ phosphors crystallized into monoclinic system with the space group of P2 1 /n. FTIR study revealed the presence of different stretching and bending vibrational bands of borate group. Bonding parameter values which obtained from the band positions of the absorption spectra revealed the covalent character which existing between the Eu 3+ ions and its surrounding ligands. Under 395 nm excitation source, the studied phosphors exhibit intense red emissions in the 617 nm wavelength region corresponding to the 5 D 0 → 7 F 2 transition of Eu 3+ ions. Judd-Ofelt (JO) intensity parameters were evaluated from the PL emission spectra in order to facilitate a study of the nature of site symmetry. From the CIE color chromaticity analysis it is evident that the prepared phosphors are found to emit an intense red light with the reasonable color coordinate and color purity under the excitation of blue light and the same may be suggested as an appropriate red component for developing white LEDs. The important radiative parameters were obtained for the emission transitions using JO intensity parameters in order to ensure the suitability of prepared phosphors for display devices and laser applications. • Eu 3+ : Sr 2 LiScB 4 O 10 phosphors were fabricated by solid state reaction method for display device applications. • Eu 3+ activated Sr 2 LiScB 4 O 10 phosphors exhibited red luminescence which was confirmed by CIE chromaticity diagram. • Higher and increasing Ω 2 values contribute to the higher degree of covalency between Eu–O bond. • Bright red light with color purity of 94% was attained in the prepared phosphors excited by 395 nm. • 0.6EuSLSB phosphor exhibit appreciable radiative properties suitable for red laser and white LEDs.

Physical and structural studies of cadmium lead boro-tellurite glasses doped with Cu2+ ions

The current manuscript explains the significance of cadmium oxide (CdO) in the field of radiation shielding materials (RSM). The effect of CdO in lead boro-tellurite glasses studied using the essential properties (density, thickness, structural studies, etc.) for RSM. The glasses with the combination of CdO–PbO–TeO2–B2O3–CuO glasses with various concentrations of CdO were prepared using melt quenching method. The incorporation of PbO and CdO enhances the density of boro-tellurite glasses, which is the most important property of RSM. The increase in density is assigned to the creation of BO4 units in the glass matrix. Absorption spectra have shown a broad absorption band in near IR region, which is the characteristic of copper-doped glasses. Optical bandgap and Urbach energy evaluated from the spectra and refractive index, molar refraction, and electronic polarizability also calculated using the spectra and the density values. Smaller values in Urbach energy values suggested the less disorder in the glasses. Spin-Hamiltonian and bonding parameter values were calculated from EPR spectra. These parameters suggested that Cu2+-surrounded ligand environment is distorted tetragonally with octahedral sites and found that all the bondings are moderately ionic in nature. A deconvoluted spectrum is used to get exact band positions in the FTIR spectra. Residual graph is drawn to know the percentage difference in experimental and simulated curves. FTIR spectra confirmed the creation of BO4 units and the presence of BO3, BO4, TeO3, and TeO4 structural units.

Exploring Environmentally Friendly Biopolymer Material Effect on Soil Tensile and Compressive Behavior.

The study of the high-performance of biopolymers and current eco-friendly have recently emerged. However, the micro-behavior and underlying mechanisms during the test are still unclear. In this study, we conducted experimental and numerical tests in parallel to investigate the impact of different xanthan gum biopolymer contents sand. Then, a numerical simulation of the direct tensile test under different tensile positions was carried out. The micro-characteristics of the biopolymer-treated sand were captured and analyzed by numerical simulations. The results indicate that the biopolymer can substantially increase the uniaxial compressive strength and tensile strength of the soil. The analysis of the microparameters demonstrates the increase in the contact bond parameter values with different biopolymer contents, and stronger bonding strength is provided with a higher biopolymer content from the microscale. The contact force and crack development during the test were visualized in the paper. In addition, a regression model for predicting the direct tensile strength under different tensile positions was established. The numerical simulation results explained the mechanical and fracture behavior of xanthan gum biopolymer stabilized sand under uniaxial compression, which provides a better understanding of the biopolymer strengthening effect.

Modified structure and spectroscopic characteristics of Sm3+/Dy3+ co-activated barium-sulfur-telluro-borate glass host: Role of plasmonic gold nanoparticles inclusion

This paper reports the pure gold nanoparticles’ (AuNPs) localized surface plasmon field mediated structural and spectroscopic modification of the Sm3+/Dy3+ co-activated barium-sulfur-telluro-borate glasses. These glass samples were synthesized via melt-quenching technique and characterized to determine the role of pure gold nanopowder embedment at different contents on their structures and optical traits. The TEM image analysis showed that the non-spherical shaped AuNPs with an average diameter of 29 nm were successfully embedded into the host glass matrix. The symmetry of the Sm3+/Dy3+ environment was increased with the increase of AuNPs contents, indicating a decreasing trend of the bonding parameter values from −0.08 to −1.25, Judd-Ofelt intensity parameter (Ω2) from 4.39×10-20 to 1.15×10-20 cm2 and crystal field strength from 9.28 to 5.99. Furthermore, the trend of the evaluated radiative parameters revealed their sensitivity to the alterations in the glass structure. The AuNPs localized surface plasmon field stimulation significantly affected the structural and spectroscopic qualities of the glasses, leading to a shift in the chromaticity co-ordinates from the white to yellowish-orange zone in the CIE 1931 color space. Overall, the proposed glass system was established to be a potential yellowish-orange light-emitting laser host matrix.

Intense red and green luminescence from holmium activated zinc-sulfo-boro-phosphate glass: Judd-Ofelt evaluation

Rare-earth ions doped oxide glasses became prospective for high quality and inexpensive solid state laser development. To fulfill this need, zinc-sulfo-boro-phosphate glasses doped with holmium ions (Ho3+) were synthesized via melt-quenching method. Prepared glasses were characterized using diverse techniques to determine the influence of varied Ho3+ contents on their optical absorption and photoluminescence (PL) emission properties. The main purpose of this paper was to determine the structural and optical correlation in Ho3+ activated phosphate-based glass host involving the red and green lasing potency of holmium. Raman, XPS and FTIR spectra were recorded to analyze the structural properties of the synthesized glasses. Furthermore, Judd-Ofelt (J-O) intensity (Ωλ with λ = 2, 4 and 6) and radiative parameters were calculated. Absorption spectra of the studied glasses disclosed thirteen characteristic peaks associated to the transitions from the lowest electronic energy level (5I8) to various excited levels in Ho3+. The PL spectra of the proposed glasses revealed 3 significant peaks allocated to the 5F4 → 5I8, 5F5 → 5I8 and 5F4 → 5I7 transitions in Ho3+. Revelation of negative bonding parameter values implied the existence of ionic bond between the ligand and Ho3+ in the prepared glass host. Values of Ω2, Ω4 and Ω6 were observed in the range of (5.11–22.62)×10−20 cm2, (9.54–13.79)×10−20 cm2 and (3.71–6.78)×10−20 cm2, respectively. Lower Ω2 value signified the higher symmetry around Ho3+, whereas higher Ω4 and Ω6 values indicated the stronger rigidity of the glass network. The achieved large stimulated emission cross-section for the red and green spectral transitions from Ho3+ ((29.47–46.01)×10−21 cm2 for 5F4 → 5I8, (31.47–39.74)×10−21 cm2 for 5F5 → 5I8 and (13.34–31.63)×10−21 cm2 for 5F4 → 5I7) clearly displayed the lasing effectiveness of the proposed glasses.

Luminescence studies on Dy3+ doped calcium boro-tellurite glasses for White light applications

A new series of Dy3+ doped calcium boro-tellurite glasses have been prepared by melt quenching technique and their spectroscopic properties were studied through FTIR, absorption luminescence and lifetime spectral measurements. FTIR studies have been made to explore the presence of various stretching and bending vibrations of different borate and tellurite groups in the prepared glasses. The bonding parameter values were estimated from the absorption band positions using Nephelauxetic ratios to examine the nature of the metal-ligand bond. The optical band gap and Urbach energy (ΔE) values were obtained from the absorption spectra to explore the electronic band structure of the studied glasses. Judd-Ofelt (JO) theory have been used to determine the JO intensity parameters (Ω2, Ω4, Ω6) following the least square fitting procedure between the experimental and calculated oscillator strength values. The luminescence spectra of the Dy3+ doped calcium boro-tellurite glasses exhibit two intense emission bands corresponding to the 4F9/2→6H15/2 and 4F9/2→6H13/2 transitions. Further, they exhibit less intense emission band due to the 4F9/2→6H11/2 transition. Luminescence spectra were characterized through CIE 1931 chromaticity diagram to obtain the dominant emission color of the prepared glasses. The JO intensity parameters and refractive index values have been used to calculate the radiative parameters such as transition probabilities (AR), branching ratios (βR) and stimulated emission cross-section (σPE) values for the observed transitions in the luminescence spectra. The decay curves of all the studied glasses found to exhibit non-exponential behavior and further to understand the energy transfer process takes place between the Dy3+ ions, the decay curves were fitted to the Inokuti-Hirayama (IH) model. The structural and optical properties of the Dy3+ doped calcium boro-tellurite glasses have been studied as a function of different metal cations (Zn, Cd, Pb and Bi) and the obtained results were discussed and compared with the similar reported glasses.

Investigations on structural and luminescence behavior of Er3 + doped Lithium Zinc borate glasses for lasers and optical amplifier applications

Trivalent Erbium doped Lithium Zinc borate glasses were prepared with the chemical composition (55–x)H3BO3+20Li2CO3+20ZnO+5LiF+xEr2O3 (where x=0.01, 0.05, 0.1, 0.5, 1.0 and 2.0mol%) following the melt quenching technique. The different BO vibrational bands and the change in coordination number of the boron with the addition of Er3+ ions in the prepared glasses were analyzed through FTIR and Raman spectra. The decreasing ionic nature was confirmed through Nephelauxetic ratios (β) and bonding parameter values (δ) from the absorption spectral measurements. The oscillator strengths and Judd-Ofelt parameters (Ω2, Ω4, Ω6) were calculated on the basis of Judd-Ofelt theory. The dependency of Ω2 parameter on the oscillator strengths of the hypersensitive transition has been studied. The radiative parameters such as transition probability (A), branching ratio (βR) and radiative lifetime (τ) which characterizes the luminescence behavior were determined from the JO parameters and refractive index values. The luminescence from the thermally coupled energy level 2H11/2+4S3/2→4I15/2 was observed under 379nm excitation and is inhomogeneously broadened (Δλeff=14nm) due to the structural disorder in the prepared glasses. The stimulated emission cross-section corresponding to the 4S3/2→4I15/2 transition is found to be higher for the LZB0.5E glass compared to the other reported literature thus it is suggested for suitable green laser applications. The luminescence behavior in the wavelength region 1400–1700nm corresponding to the 4I13/2→4I15/2 transition at 980nm excitation was also observed and its suitability for optical amplifier applications and NIR laser have been discussed with parameters such as optical gain bandwidth (ΔG), Figure of Merit (FOM) and stimulated emission cross-section (σe). Of all the studied glasses, LZB0.5E glass possesses higher values of ΔG=613.8×10−28cm3, FOM=40.9×10−24cm2s and σe=93×10−22cm2 compared to the reported literature thus suggesting its suitability for optical amplifier and NIR laser applications.

Synthesis and Structural Characterization of 2-Hydroxy-5- (Phenyldiazenyl) Benzaldehyde Oxime - A Theoretical Approach

The 2-hydroxy-5-(Phenyldiazenyl)benzaldehyde oxime (PDBO) was synthesized and characterized. The spectral investigations such as FT-IR, FT-Raman and UV-Vis spectra were recorded. The bond parameter values were calculated at DFT/B3LYP/6- 311++G(d,p) level of theory. The observed spectral results were compared with the computed wavenumber. The complete vibrational assignments of wavenumbers were made on the basis of TED. The first order hyperpolarizability, intra-molecular charge transfer and band gap energy were studied using B3LYP/6-311++G(d,p) calculation. The electronic transition was studied using UV-Vis spectrum and the observed values were compared with the theoretical values. The MEP, Mulliken charges and thermodynamic parameters of the title molecule was also analyzed using the same level of basis set.

Vanadyl ion (VO 2+) as a spectroscopic probe of metal binding to nitrohumic acid

A coal nitrohumic acid (CNHA) of high nitrogen content (compared with natural humic acid) was obtained by extraction from nitric acid oxidation products of a mineral coal. It was studied by e.s.r. and i.r. spectroscopies, using VO 2+ as a probe of metal ion complexation sites. Spectroscopic data and a LCAO-MO ligand field calculation were used to evaluate the bond parameters of vanadyl-coal nitrohumic acid complex (VO-CNHA). In spite of the high nitrogen content of CNHA, plots of hyperfine coupling constants 〈 A〉 versus isotropic 〈 g〉 values indicate that nitrogen is not a donor atom in the complexation sites of these materials. The bond parameter values, 〈 A〉 and 〈 g〉, and i.r. data suggest that VO 2+ groups (in the CNHA molecules) are at sites with C 4v symmetry having o-hydroxycarboxylic aromatic (salicylic) acids as equatorial ligands.