Cambridge Serial Total Energy Package Research Articles

First-principles calculations to investigate structural, electronic and optical properties of Na based fluoroperovskites NaXF3 (X= Sr, Zn)

A theoretical study to investigate the electronic, optical and structural properties of sodium-based cubic fluoro-perovskite NaXF3 (where X = Sr, Zn), using density functional theory (DFT) based CASTEP (Cambridge Serial Total Energy Package) code with ultra-soft pseudo-potential USP plane wave and Perdew Burke Ernzerhof (PBE) exchange-correlation functional of Generalized Gradient Approximation (GGA), is reported. The findings show that both compounds are in a stable form with a cubic structure. The calculated elastic constants also meet the mechanical stability criteria. NaSrF3 is brittle, while NaZnF3 is ductile, according to Pugh's criteria. The electronic band structure calculations reveal that NaSrF3 has a direct and NaZnF3 has an indirect band gap. The finding of band gap is agreed well with the data that is already available. The degree of localized electrons in different bands is confirmed by partial density of states (PDOS) and total density of states (TDOS). By fitting the dispersion relation for the hypothetical dielectric function scale to the corresponding peaks, the optical transitions in both compounds were investigated. Both materials are insulators at 0 K and semiconductor at high temperature. However, the dielectric function's imaginary component dispersion exposes its broad range of energy transparency. As a result, it can be inferred that these materials could be used to capture the ultraviolet region in optoelectronics.

The Physical Properties of ThCr2Si2- Type Co-based Compound SrCo2Si2: An ab-initio Study

In this article, we have studied the mechanical, electronic, and optical features of ThCr2Si2- type compound SrCo2Si2. The investigation has been done by using the first-principles method depend on the density functional theory (DFT) and the calculations were completed with the Cambridge Serial Total Energy Package (CASTEP) code. The optimized lattice parameters are well in accord with the existing synthesized values. The investigated elastic constants for this compound are positive which ensured the mechanical stability of this phase. The calculated values of Pugh’s ratio and Poisson’s ratio ensure the brittle character of SrCo2Si2. The universal anisotropic constant AU ensures the anisotropic behavior of SrCo2Si2.The softness nature of SrCo2Si2 is confirmed by the bulk modulus calculations. The overlapping of the valence band and conduction band near the Fermi level indicates the metallic nature of SrCo2Si2. At the Fermi level, the major contribution comes from Co-3d and Si-3p states. The large reflectivity in the high-energy region indicates that this compound might be useful as coating materials for reducing solar heating. The photoconductivity and absorption begins with zero photon energy which also ensures the metallic nature of SrCo2Si2.

Pressure induced semiconductor to metal phase transition in cubic CsSnBr3 perovskite

Phase transitions in metal halide perovskites triggered by external provocations produce significantly different material properties, providing a prodigious opportunity for comprehensive applications. In the present study, the first principles calculation has been performed with the help of density functional theory using the Cambridge Serial Total Energy Package code to investigate the physical properties of lead-free CsSnBr3 metal halides under various hydrostatic pressures. The effect of pressure is determined in the range of 0–28 GPa by the generalized gradient approximation and Becke, three-parameter, Lee–Yang–Parr functions. Subsequently, a significant change is observed in the lattice constant and volume with increasing pressure. The electronic band structure shows a semiconductor to metal phase transition under elevated pressure. The investigation of optical functions shows that the absorption edge of the CsSnBr3 perovskite is shifted remarkably toward the low energy region (red shift) with improved pressure up to 16 GPa. In addition, the absorptivity and dielectric constant also upsurge with the applied hydrostatic pressure. Finally, the mechanical properties reveal the fact that the CsSnBr3 perovskite is mechanically stable and highly ductile; the ductility is increased with increasing pressure. This type of semiconductor to metal phase transition may inspire a wide range of potential applications.

Combined Experimental and DFT-TDDFT Characterization Studies of Crystalline Mesoporous-Assembled [ZrO2]NPs and [DPPP + Gly/ZrO2]C Nanocomposite Thin Film

[(Z)-2-((1,3-bis(diphenyl phosphaneyl) propylidene) amino) acetic acid/Zirconium oxide nanoparticles] composites thin film [DPPP + Gly/ZrO2]C is synthesized by utilizing physical vapor deposition (PVD) with a speed rate of 2000 rpm/30 s. The optimization of the samples was performed using density functional theory (DFT) by DMol3 and Cambridge Serial Total Energy Package (CASTEP) program. The [DPPP + Gly/ZrO2]C nanocomposite thin film is examined by different techniques including scanning electron microscope (SEM), X-ray diffraction (XRD), proton nuclear magnetic resonance (1HNMR), and Fourier transform infrared (FT-IR). The [DPPP + Gly/ZrO2]C nanocomposite thin film with the thickness (150 ± 5 nm) is fabricated at optimization conditions. The optical constants (refractive index, $$n\left(\lambda \right)$$ , extinction coefficient, $$k\left(\lambda \right)$$ , dielectric constants ( $${\epsilon }_{1}\left(\lambda \right)$$ and $${\epsilon }_{2}\left(\lambda \right)$$ ) and optical conductivity ( $${\sigma }_{1}\left(\lambda \right)$$ and $${\sigma }_{2}\left(\lambda \right)$$ )) for [DPPP + Gly/ZrO2]C nanocomposite thin film are computed and compared by using experiment and CATSTEP methods. The optical properties of simulated FTIR, XRD, and CATSTEP of the considered fiber nanocomposites are in somewhat compatible with the experimental study. The nano nanocomposite thin films present a promising result to be a good candidate for optoelectronics and solar cell applications.

Metal-organic framework-derived rodlike AgCl/Ag/In2O3: A plasmonic Z-scheme visible light photocatalyst

A novel metal–organic framework (MOF)-derived rodlike AgCl/Ag/In2O3 plasmonic photocatalyst has been successfully prepared by electrostatic self-assembly, co-precipitation, in-situ photoreduction, and calcination. The photocatalytic activity of the samples was systematically investigated by photocatalytic tetracycline (TC) oxidation and Cr(VI) reduction under visible light irradiation. Among the as-prepared samples, AgCl/Ag/In2O3-2 displayed the most effective photocatalytic activity. For photocatalytic TC oxidation, the apparent rate constant of AgCl/Ag/In2O3-2 was 0.5036 min−1, which was 2.7, 6.5, and 1.8 times higher than that of In2O3 (0.1845 min−1), AgCl/In2O3 (0.1544 min−1) and Ag/In2O3 (0.2850 min−1), respectively. In addition, AgCl/Ag/In2O3-2 also exhibited the highest activity for photocatalytic Cr(VI) reduction, and the photocatalytic Cr(VI) reduction rate of AgCl/Ag/In2O3-2 in 3hrs could reach 94.8%. The superior photocatalytic activity was due to the enhanced absorption in the visible light region caused by localized surface plasmon resonance (LSPR) and the efficient interfacial charge migration and separation in AgCl/Ag/In2O3 samples. Moreover, the intermediates formed in the photocatalytic TC oxidation were identified by GC–MS. Finally, a series of characterizations and simulations (density functional theory, cambridge serial total energy package, and finite difference time domain) were carried out to demonstrate the plasmonic Z-scheme photocatalytic mechanism.

Synthesis of novel keto-bromothymol blue in different media using oxidation–reduction reactions: combined experimental and DFT-TDDFT computational studies

A crystalline ((3-bromo-5-isopropyl-2-methyl-4-oxocyclohxa-2,5-dien-1-yl)methyl 4ʹ-hydroxy-5ʹ-isopropyl-2ʹ-methyl-[1,1ʹbiphenyl]-2-sulfonate) [BTB]Keto was synthesized in different media at 25 °C based on an oxidation method in the presence of potassium permanganate. The redox reactions occur in alkaline and acidic media. In alkaline medium, two distinct stages were observed: The first stage was relatively fast and the second stage was relatively slow. The first step coexists with the formation of intermediate complexes involving transient species relatively quickly of the blue hypomanganate (V) and green manganate (VI). The slowly decomposed intermediate formed to produce soluble colloidal manganese (IV) and the BTB keto-derivatives as second slow-stage oxidation products. But in acidic medium, oxidation reaction occurs in one stage because the first stage was found to be very fast and cannot be followed and the second stage was found to be slow so the reaction occurs in one stage (slow stage) to give rise to the final oxidation product [BTB]Keto. Thin films were produced through physical vapor deposition. Both the resulting dye particles and prepared thin films were deeply discussed using various techniques including Fourier transform infrared (FTIR), X-ray diffraction (XRD), ultraviolet–visible spectroscopy (UV–Vis), and optical properties. DMol3 and Cambridge Serial Total Energy Package (CASTEP) program performed the optimization of the samples using density functional theory (DFT). An XRD and FT-IR study established the structural properties of the resultant dye. The XRD tests of thin films (monoclinic 2) display crystal structure. An optical measurement found that with growing photon energy the optical constants (refractive index n, absorption index k, dielectric constants, and optical conductivity) decreased. The optical properties of the dye thin films found in model FTIR, XRD, and CATSTEP are in strong alignment with the experimental research. The dye thin films show a compelling outcome to be a successful choice for applications in optoelectronics and solar cells. Experimental XRD data of both [BTB]TF and [BTB]keto thin films

DFT based first principles study of novel combinations of perovskite-type hydrides XGaH3 (X = Rb, Cs, Fr) for hydrogen storage applications

Hydrogen storage has become a challenge for researchers of this era because it is a cheap, clean, and non-pollutant element existing in nature. The current study has been performed in order to calculate the structural, electronic, optical, and magnetic properties of perovskite hydrides XGaH3 (X = Rb, Cs, Fr) through the Cambridge serial total energy package code based on density functional theory. The comprehensive investigations have been made while utilizing three cations (Rb, Cs, and Fr) in the cubic form of the ABH3 symmetry phase. The electronic properties of the considered hydrides have been investigated to determine bandgap, total density of states, and partial density of states, and their trends are devised against frequency (eV) of incident radiations. XGaH3 hydrides have shown metallic behavior because no energy bandgap is noticed near the Fermi level. The lattice constants of RbGaH3, CsGaH3, and FrGaH3 by utilizing the Perdew–Burke–Ernzerhof-Generalized Gradient Approximation (PBE + GGA) functional are found to be 4.0754 Å, 4.2137 Å, and 3.1237 Å. The local density approximation functional has also been used for calculations of lattice parameters, which are observed to be 3.9287 Å, 4.0673 Å, and 3.9818 Å, respectively. Anti-ferromagnetism is observed through magnetic analysis of the studied hydrides XGaH3 (X = Rb, Cs, Fr). Regarding the optical analysis, FrGaH3 is found to be a more suitable material for hydrogen storage. These novel materials exhibit minimum energy loss with maximum conductivity. The gravimetric ratio for hydrogen storage capacity is determined to be 2.5 wt. %, 2.0 wt. %, and 2.1 wt. % for RbGaH3, CsGaH3, and FrGaH3, respectively. The present computational calculations of these hydrides are attempted for the first time, which may provide exceptional improvements for applications in hydrogen storage.

Combined experimental and TDDFT computations for the structural and optical properties for poly (ortho phenylene diamine) thin film with different surfactants

Poly(ortho-phenylenediamine) micro-rods (PoPD) are synthesized in the acidic medium at 25 °C by an oxidative polymerization method in the absence or the presence of a soft template including the following surfactants para toluene sulfonic acid (PoPD-PTS) and trisodium citrate (PoPD-TSC). Then, the thin films of poly(ortho-phenylenediamine) (PoPD)F, toluene sulfonic acid (PoPD-PTS)F, and trisodium citrate (PoPD-TSC)F are fabricated using the physical vapor deposition method (PVD). The fabricated thin films are characterized by several techniques includes Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), X-ray diffraction analysis (XRD), UV–Vis spectroscopy (UV–Vis), scanning electron microscopy (SEM), and optical properties are interpreted in-depth. The optimization for the samples is carried out by applying density functional theory (DFT) with DMol3 and Cambridge Serial Total Energy Package (CASTEP) program. XRD measurements of thin film showed a crystal structure of monoclinic 2, and there is an increase of polymer crystallite size when used PTS and TSC surfactants in the preparation of the polymer. The study of surface morphology shows a smooth surface with uniform micro-rods for the resulting polymer. The optical constants including refractive index (n), absorption index (k) are calculated. Based on the optical measurements, the optical constants decrease with increasing photon energy while optical conductivity, and dielectric constants increase. Following the experimental analysis, the optical properties of simulated FT-IR, XRD, and CATSTEP are in good agreement with the experimental ones. (PoPD-PTS)F and (PoPD-TSC)F films are a good applicant for optoelectronics and solar cells.

Theoretical investigation of the electronic structure, elastic, dynamic properties of intermetallic compound NiBe under pressure

From the beryllide group, NiBe is a hybrid material of CsCl (B2) type structure and presents a large range of stoichiometry. In this paper, we have studied the structural, electronic, elastic, and dynamic properties of NiBe intermetallic compound under pressure by performing ab initio density functional theory using the Cambridge Serial Total Energy Package (CASTEP). In B2 structure, we have obtained the lattice constant ( $${A}_{\mathrm {0}}$$ ), equilibrium volume ( $${V}_{\mathrm {0}}$$ ), bulk modulus ( $${B}_{\mathrm {0}}$$ ) and its pressure derivative ( $${B}_{0}$$ ’) and elastic constants. We have quantitatively analyzed the band structure and the corresponding density of states (DOS). We have also estimated the mechanical stability and brittle/ductile behaviors of this compound based on the computed elastic constants. It is found that this structure is stable between 0 and 50 GPa pressure for NiBe compound. Finally, the changing degree of anisotropy with pressure was analyzed in three and two dimensions.

Detailed structural, mechanical, and electronic study of five structures for CaF2 under high pressure* *Project supported by the National Natural Science Foundation of China (Grant No. 61971229).

Detailed density functional theory (DFT) calculations of the structural, mechanical, thermodynamic, and electronic properties of crystalline CaF2 with five different structures in the pressure range of 0 GPa–150 GPa are performed by both GGA (generalized gradient approximation)-PBE (Perdew–Burke–Ernzerhof) and LDA (local density approximation)-CAPZ (Cambridge Serial Total Energy Package). It is found that the enthalpy differences imply that the fluorite phase → PbCl2-type phase → Ni2In-type phase transition in CaF2 occurs at P GGA1 = 8.0 GPa, P GGA2 = 111.4 GPa by using the XC of GGA, and P LDA1 = 4.5 GPa, P LDA2 = 101.7 GPa by LDA, respectively, which is consistent with previous experiments and theoretical conclusions. Moreover, the enthalpy differences between PbCl2-type and Ni2In-type phases in one molecular formula become very small at the pressure of about 100 GPa, indicating the possibility of coexistence of two-phase at high pressures. This may be the reason why the transition pressure of the second phase transition in other reports is so huge (68 GPa–278 GPa). The volume changed in the second phase transition are also consistent with the enthalpy difference result. Besides, the pressure dependence of mechanical and thermodynamic properties of CaF2 is studied. It is found that the high-pressure phase of Ni2In-type structure has better stiffness in CaF2 crystal, and the hardness of the material has hardly changed in the second phase transition. Finally, the electronic structure of CaF2 is also analyzed with the change of pressure. By analyzing the band gap and density of states, the large band gap indicates the CaF2 crystal is always an insulator at 0 GPa–150 GPa.

Study on the Optical Luminescence Properties of Li2TiO3: Mn4+ and Cr3+

Abstract We studied the optical luminescence properties of Li2TiO3: Mn4+ based on first-principles calculations. The optical luminescence properties such as Mn-O distance, molecular orbital (MO) energy, crystal field splitting, multiplet energy levels, and Coulomb interaction are discussed in detail. The impact of lattice relaxation was examined through geometry optimizations based on first-principles band-structure calculations using Cambridge Serial Total Energy Package (CASTEP) software. Both Discrete Variational-Xα (DV-Xα) and the Discrete Variational Multi-electron (DVME) software were used to estimate the optical luminescence properties. Here we also predicted the optical luminescence properties of Li2TiO3: Cr3+. The results imply that the multiplet energy levels tend to decline in the order of Mn4+ to Cr3+. The integral Coulomb's decreasing tendency is in excellent agreement with the declining tendency of 2E, 2T1, 2T2 energies of Li2TiO3: Mn4+ and Li2TiO3: Cr3+.

Synthesis and characterization of Poly (ortho-aminophenol-co-para-toluidine) and its application as semiconductor thin film

Hydrochloric acid doped poly (ortho-aminophenol–co-para-toluidine) as a conjugated semiconducting copolymer is synthesized in acidic medium via the oxidative polymerization method. The spin coating technique is applied to deposit with appropriate adhesion of doped copolymer thin film. The resulting doped poly (ortho-aminophenol–co-para-toluidine) (POAPT) thin film is characterized by the various techniques to explore its structural, morphological, and optical properties. Density-functional theory (DFT) calculations were implemented utilizing Cambridge Serial Total Energy Package (CASTEP) from Accelrys based on a plane-wave pseudopotential. The optical dispersion of poly (ortho-aminophenol–co-para-toluidine) thin film is expressed in the single oscillator terms of Wemple–Didomenico (WD) model. The parameters Eg is 2.02 eV, n and k (at 2.36 eV) are 1.73 and 3.27×10-8, respectively, n∞ is 1.633, λo is 172.65 nm and So is 2.126 nm-2. Based on the resulting data of optical analysis and conductivity the doped poly (ortho-aminophenol–co-para-toluidine) thin film was found to have promising applications in optoelectronic devices area.

Novel synthesis, DFT and investigation of the optical and electrical properties of carboxymethyl cellulose/thiobarbituric acid/copper oxide [CMC + TBA/CuO]C nanocomposite film

A novel synthesis blend of sodium carboxymethyl cellulose (CMC) with thiobarbituric acid (TBA) [CMC + TBA]B has been doped with CuO to study the optical and direct electrical (DC) properties of [CMC + TBA/CuO]C nanocomposite films. Different characterization techniques for [CMC]TF, [TBA]TF, [CMC + TBA]B and [CMC + TBA/CuO]C such as Fourier-transform infrared spectroscopy (FTIR), Ultraviolet–visible spectroscopy (UV-Vis), X-ray diffraction (XRD), Scanning electron microscopy (SEM) and optical properties have been used. SEM showed a good dispersion of copper oxide nanoparticles [CuO]NPs on [CMC + TBA]B film surface. The dielectric constant e(ω), optical conductivity σ(ω) and DC properties increased and demonstrated wave-like performance with increasing [CuO]NPs ratio at hν range of 0.7 eV – 5.0 eV. Copper content [CuO]NPs increases lead to the formation of a wide variety of 3D-semiconductor networks within [CMC + TBA]B film matrix which increase optical conductivity. The optimization was performed using density functional theory (DFT) by DMol3 and Cambridge Serial Total Energy Package (CASTEP). In Experimental section by using Tauc’s equation, the results clearly show that the values of optical energy band gap $$ {E}_g^{Opt} $$ decreases from 2.978 eV for [CMC]TF, 2.725 eV for [TBA]TF, 2.625 eV for [CMC + TBA]B to 2.488 eV for [CMC + TBA/CuO]C. The simulated FTIR, XRD, and optical properties by Gaussian software and CATSTEP are in great agreement with the experimental study. The [CMC + TBA/CuO]C presents a good candidate for optoelectronics and solar cell applications.

Novel synthesis, structure characterization, DFT and investigation of the optical properties of cyanine dye/zinc oxide [4-CHMQI/ZnO]C nanocomposite thin film

A novel synthesis of (E)-4-(4-carboxy-3-hydroxystyryl)-1-methylquinolin-1-ium iodide nanostructure thin film has been doped with zinc oxide nanoparticles to study the optical properties of nanocomposite films. Different characterization techniques for nanocomposite film such as Fourier-transform infrared spectroscopy, ultraviolet–visible spectroscopy, x-ray diffraction, scanning electron microscopy and optical properties have been used. The scanning electron microscopy showed a good dispersion of zinc oxide nanoparticles on nanocomposite film surface. The dielectric constant and optical conductivity increased and demonstrated wave-like performance with increasing zinc oxide nanoparticles ratio at hν range of 0.7eV – 5.0 eV. zinc oxide nanoparticles content increases lead to the formation of a wide variety of three dimension-semiconductor networks within nanocomposite film matrix which increase optical conductivity. The density functional theory by thee dimension molecular simulation software and Cambridge serial total energy package was used for optimization of novel cyanine dye and nanocomposite as isolated molecule. From the ultraviolet–visible spectrum of nanocomposite thin film, the direct and indirect optical energy gap values are 2.041 eV and 1938 eV by using Tauc`s equation, respectively, related to direct and indirect transitions of electrons. By using thee dimension molecular simulation software mothed with density functional theory simulation, the highest occupied molecular orbital and lowest unoccupied molecular orbital values for nanocomposite as isolated molecule are 4.735 eV and 3.531 eV, respectively. The simulated Fourier-transform infrared spectroscopy, ultraviolet–visible spectroscopy, x-ray diffraction and optical properties by Gaussian software and Cambridge serial total energy package are in great agreement with the experimental study. A successful choice for optoelectronics and solar cell applications are the novel cyanine dye thin film and its nanocomposite.

A DFT study of two-dimensional CdS/TiS2 on isotropic chalcogenide AgSbTe2 thermoelectric material: Electronic charge transfer and optical properties

Calculations of AgSbTe2 thermoelectric material and 2d CdS/TiS2 and their heterostructures were carried out using Density Functional Theory in Cambridge Serial Total Energy Package code as implemented in Material Studio 2018 software. The work function, thermal transport, electronic and optical properties were calculated. The results revealed that the heterostructures are possible to be achieved with improved properties. The electronic and thermal transport properties were likened with the description of equations derived from Boltzmann transport theory and Mott expressed in the maximum achievable Figure merit. Orbital contributions from the electron movement show valence and conduction band atomic shells.

Improvement of the thermal stability and optical properties for poly (ortho phenylene diamine) using soft templates

A crystalline protonated-poly (ortho phenylenediamine) microrods [POPDA] with ladder-type structure was elaborated at room temperature in an acidic medium. The synthesis method was based on an oxidative polymerization, including sodium dodecyl sulphate [POPDA-SDS] and glycine [POPDA-Gly]. In case of absence or soft template presence, thin films from the considered polymers were fabricated by physical vapor deposition (PVD). Both the resulting polymer flakes and prepared thin films were studied via different techniques such as XRD, FTIR, TGA, SEM, UV–Vis, while optical properties are discussed in detail. The optimization of the samples was performed using Cambridge Serial Total Energy Package (CASTEP) program and density functional theory (DFT) by DMol3. Structural properties of resulting polymers were determined by XRD and FT-IR analysis. XRD results of thin films showed (Monoclinic 2) crystal structure and showed an increase in crystallite size for the polymer, prepared in the presence of SDS surfactants. The surface morphology study revealed the existence of a smooth surface with a significant number of uniform microrods. The optical calculation showed that absorption index k, refractive index n, dielectric constants, and optical conductivity decrease with photon energy increase. The optical properties of simulated FTIR, XRD, and CATSTEP of the considered polymers present a respectable level of experimental study agreement. The polymer thin films present a promising case to be the right candidate for optoelectronics and solar cell applications.

Molecular simulation and microtextural characterization of quartz dissolution in sodium hydroxide

This study uses empirical experimental evidence and Material Studio simulations to explain the interaction of sodium hydroxide (NaOH) with quartz. Density functional theory (DFT) calculations were carried out using the Cambridge Serial Total Energy Package. In addition, quartz grains subjected to dissolution in NaOH were characterized using scanning electron microscopy. The so-called O-middle termination in the quartz tetrahedron structure, typified by a solitary exposed oxygen atom at the surface, is the most susceptible SiO2 terminations to NaOH attack, as it is associated with the lowest surface energy. The adsorption energy values are − 1.44 kcal/mol and − 5.90 kcal/mol for a single atom layer and five-layered atomic structure, respectively. The DFT calculation reveals intramolecular energy is the dominant adsorption energy, followed by a weak van der Waals energy. The NaOH adsorbed on quartz (001) surface constitutes a lower band gap of 0.138 eV compared to cleaved quartz (001) surface (0.157 eV). In addition, the energy range of NaOH adsorbed on quartz is wider (− 50 to 10 eV), compared to (001) quartz (− 20 to 11 eV). The dissolved quartz showed the precipitation of sorbed silicate phases due to incongruent reactions, which indicates new voids and etch pits can be created through the cleaving of the sodium silicates sorbed into the quartz surface. The adsorption energy for NaOH interactions with reservoir sandstone was significantly higher compared to the solitary crystal grains, which can be attributed to the isotropic deformation of a single crystal, and non-uniform deformations of adjacent grains in granular quartz of sandstone reservoir. It can be inferred that exposure to NaOH will affect the structure and reactivity of quartz. The quartz surface textural study indicates that dissolution of crystalline (granite) and clastic rocks (sandstone) is critical to the development of voids, which will improve permeability by providing channels and routes for the passage of hydrothermal and reservoir fluids.

A computational insight of electronic and optical properties of Cd-doped BaZrO3

First principles calculations are carried out to explore the structural, electronic and optical properties of Pure and Cd-doped BaZrO3, an oxide-based perovskite material. To investigate these properties, Ultra-soft pseudo-potential (USP) is used as incorporated in Cambridge Serial Total Energy Package (CASTEP). In this system, the generalized gradient approximation (GGA) proposed by Perdew-Burke Erzenhoff (PBE) is used for exchange correlation potential. Cadmium (Cd) doping at Ba-site is more favorable as compare to Zr-site because new gamma points occurred which not only affects the electronic structure of the BaZrO3 but also reduces the band gap from 3.127eV to 1.326eV and a transformation from indirect to direct band gap occurred. After doping, Fermi level shifted towards valance band which exhibits the characteristic of p-type semiconductor material. In optical properties, the absorption spectrum, refractive index (2.73), dielectric constants, reflectivity and energy loss function of the doped in comparison with pure material is presented. It has good optical response in UV region. The doping changes the optical behavior of BZO drastically thus making this material more effective for optoelectronic applications.

A non-empirical lattice-relaxation estimation of TM3+ doped α-Al2O3

We investigated the effect of lattice relaxation in the trivalent transition metal ions doped α-Al2O3 crystal (α-Al2O3: TM3+). The transition metal ions are Sc3+, Ti3+, V3+, Cr3+, Mn3+, Fe3+, and Co3+. The lattice relaxation effect was considered by comparing two different methods such as Shannon’s crystal radii methods and Cambridge Serial Total Energy Package (CASTEP) methods. In the Shannon’s crystal radii methods, the lattice relaxation effect was estimated as the ratio of the crystal radii of the substituted ion and the replaced ion. On the other hand, in the CASTEP method, the lattice relaxation effect was estimated by geometry optimization. The detail results show that in the case of Shannon’s crystal radii method, the lattice relaxation ratio was ca. 111.0 - 100.5%. Whereas in the case of CASTEP method, the lattice relaxation ratio was ca. 107.8 - 102.1%. However, the lattice relaxation ratio of α-Al2O3: Sc3+, Ti3+, V3+, Cr3+, Mn3+, Fe3+, and Co3+ is unique depends on the ion type.

Synthesis, characterization, and DFT modeling of novel organic compound thin films derived from 2-amino-4-(2-hydroxy-3-methoxyphenyl)-4H-thiazolo[3,2-a][1,3,5]triazin-6(7H)-one

A smooth and effective protocol was proven to produce 2-amino-4-(2-hydroxy-3-methoxy-phenyl)-6-oxo-4H-thiazolo[3,2-a][1,3,5]triazine [2aTZ] via one-pot ternary condensation of easily available mercaptoacetic acid, o-vanillin and dicyandiamide along with ammonium acetate (CH3COONH4) as a catalyst. The chemical structure of the compound and its thin-film [2aTZ]TF were characterized by Fourier-Transform Infrared spectroscopy (FT-IR), Proton Nuclear Magnetic Resonance (1HNMR), Carbon Nuclear Magnetic Resonance (13CNMR), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) analyses. The optimization of the molecular structure, vibrational spectra and optical properties have been accomplished depends on the density functional theory (DFT) utilizing DMol3 and Cambridge Serial Total Energy Package (CASTEP) programs for [2aTZ] as the isolated molecule and crystal models. It's very well-referred to the molecule's structure and their contacts. They are equated with data calculated by means of various theoretical methodologies. [2aTZ]TF is fabricated by spin coating (250 ± 3 nm) and its optical properties (optical band gaps, EgOpt, absorption index, k, reflective index, n, dielectric constant, ε, and optical conductivity,σ) are also investigated. The high accurateness of the new [2aTZ] along with its suitable optical bandgap provided us to construct a photodetector and demonstrating its potential in optoelectronic implementations.