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dz2 Orbitals Mediated Bound Magnetic Polarons in Ferromagnetic Ce Doped BaTiO3 Nanoparticles and its Enriched Two Photon Absorption Cross Section
摘要： Enriched ferromagnetism and two photon absorption (TPA) cross section of perovskite BaTiO3 nanoparticles are indispensible for magnetic and optical data storage applications. In this work, the hydrothermally synthesized Ce doped BaTiO3 nanoparticles exhibit the maximum room temperature ferromagnetism (4.26×10-3 emu/g) at 4 mol% due to the increase of oxygen vacancies as evidenced by X-ray photoelectron, electron spin resonance spectroscopies and density functional theory (DFT) calculations. Hence, the oxygen vacancy constituted bound magnetic polaron (BMP) model has been invoked to explain the enhancement of ferromagnetism. BMP theoretical model indicates the increase of BMP magnetization (M0, 3.0 to 4.8×10-3 emu/g) and true spontaneous moment per BMP (meff, 4 to 9.88×10-4 emu) on Ce doping. DFT calculations show that BMPs mediate via Ti d orbitals leading to the ferromagnetism. Besides, it is understood that the magnetic moment induced by Ce at Ba site is higher than Ce at Ti site in the presence of oxygen vacancies. Open aperture Z-scan technique displays the highest TPA coefficient β (7.08×10-10 m/W) and TPA cross section σTPA (455×104 GM) at 4 mol% of Ce as a result of robust TPA induced excited state absorption. A large σTPA is attributed to the longer excited state lifetime τ (7.63 ns) of charge carriers created by oxygen vacancies and Ce ions which encounter several electronic transitions in the excited sub-states.
关键词： Ce doping,oxygen vacancies,bound magnetic polarons,two photon absorption,DFT calculations,Z-scan technique,BaTiO3 nanoparticles,ferromagnetism
更新于2025-11-19 16:56:35
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A Spectroscopic Study of Tautomeric Equilibrium of Salicylideneaniline in ZSM-5 Zeolites
摘要： Salicylideneaniline (SA) sorbed in cation-exchanged M-ZSM-5 (M = H+, Li+, Na+, K+, Rb+, Cs+ and Zn2+) zeolites was studied by spectroscopic techniques assisted by quantum-chemical calculations. The nature of extra-framework cations present in the zeolite void was found to affect the spectral signature of the sorbed SA molecule that points to the shift of tautomeric equilibrium between the enol and keto forms. Small size cations, such as H+ and Li+, stabilize a cis-keto SA tautomer along with a enol one in the zeolite structure. The calculations indicate that the sorbed cis-keto tautomer may have the dipole large enough to be considered as a zwitterion. New features appearing in the spectra with the increase of the cation size were attributed to the presence of trans-keto SA tautomer, which up to now has been observed only in time-resolved spectroscopic experiments. A strong interaction of the molecule with cations in Zn-ZSM-5 zeolite results in the chelation of enol SA with the divalent Zn2+ ions. The results of the study suggest that the tautomeric equilibrium of molecules belonging to the Schiff base family can be tuned by the con?nement in the nanoporous materials via a choice of topology of zeolite framework and the nature of extra-framework cations.
关键词： spectroscopy,tautomer,DFT calculations,ZSM-5,equilibrium,salicylideneaniline,zeolite
更新于2025-11-19 16:56:35
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0D/2D AgInS2/MXene Z-scheme heterojunction nanosheets for improved ammonia photosynthesis of N2
摘要： In order to explore efficient photocatalysts for N2 reduction reaction (NRR), 0D AgInS2 nanoparticles and 2D MXene (Ti3C2) nanosheets with different mass ratios are employed for building Z-scheme heterostructures. The resultant hybrids exhibit excellent interfacial charge transfer ability according to their optical and photo-electro properties. As a result, the obtained composite (30 wt% AgInS2) shows significant improvement on the photocatalytic performance for N2 fixation with a high ammonia yield rate of 38.8 μmol/(g·h) under visible-light illumination (> 400 nm). Meanwhile, the DFT calculations show that the activation of N2 in a dinuclear end-on bound structure could lead to high adsorption energy (Ead = -5.20 eV). Moreover, the mechanism of enhanced photocatalytic activity was proposed in terms of the quantum calculation between Ti3C2 and N2. This work provides new systems for enhanced NRR performance.
关键词： N2 reduction,DFT calculations,AgInS2/MXene heterojunction,Photocatalysis
更新于2025-11-14 15:28:36
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First titanium square fragment {Ti4(μ4-Se)(μ2-Se2)4} in its selenoiodide: Synthesis and structure of Ti4Se9I6
摘要： The first titanium selenoiodide Ti4Se9I6 was synthesized as black crystals by heating of Ti, Se, and I2 at 250 °C in 5:9:5 M ratio. The crystal structure of the compound was solved by X-ray single-crystal diffractometry (sp. gr. P-1, a = 7.9652(10), b = 10.3390(15), c = 15.692(2) ?; α = 79.116(7)°, β = 75.861(7)°, γ = 71.437(7)°; Z = 2) with final R1 = 0.0397. The structure includes square {Ti4(μ4-Se)(μ2-Se2)4} fragment coordinated by four terminal and four bridging μ2-I atoms. Ti4+ has d0 configuration, and stability of the structure fragments is provided by metal to ligand bonding which was confirmed by DFT calculations.
关键词： Metal chalcohalides,Titanium,Square complex,Synthesis,Selenide,X-ray crystal structure,Chain structure,DFT calculations,Iodide
更新于2025-11-14 15:14:40
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Spectroscopic and theoretical studies of potassium sodium l-(+)-tartrate tetrahydrate and l-tartaric acid used as precursors for in situ laser-induced deposition of the catalytically active copper microstructures
摘要： In this work we study the influence of l-(+)-КNaC4H4O6 × 4H2O (KNaT) and l-H2C4H4O6 (H2T) on the complexation processes occurring during in situ laser-induced catalytic destruction of the organic components of the aqueous solutions with formation of the unsaturated hydrocarbons. For that purpose, ATR-FTIR, Raman, IR, and NIR spectroscopy as well as quantum chemical calculations were implemented. It was observed that hydration of T2? anion via carboxylate groups is stronger than that via hydroxyl groups. We also established the changes in the spectral characteristics of the absorption bands corresponding to vibrations of T2?, HT?, and H2T, at solid state-liquid and acid-salt transitions, depending on concentration of the solution components and the [OH?]/[H2T] ratio. Finally, it was shown that ethylene is a main product of the catalytic destruction of the copper tartrate complexes.
关键词： IR,Laser-induced copper deposition,DFT calculations,Tartaric acid,ATR-FTIR,Catalysis,NIR,Raman spectroscopy,Sodium potassium tartrate tetrahydrate
更新于2025-10-22 19:40:53
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B-Doping-Enhanced Stability of Phosphorene/Graphene Heterostructures
摘要： Two-dimensional material heterostructures show large surface area and unusual electronic properties, being used in nanoelectronic devices, energy storage devices, and sensors. Doping can improve stability of the heterostructures. Structural and electronic properties of B–doped phosphorene/graphene heterostructures are studied using ?rst-principles calculations. B doping in phosphorene enhances the interlayer charge transfer from phosphorene to graphene. Importantly, B doping creates strong chemical bonding at the interface, which improves stability of phosphorene/graphene heterostructures. The band gap is opened up to 0.53 eV by B doping.
关键词： heterostructure,DFT calculations,graphene,phosphorene,chemical bonding
更新于2025-09-23 15:23:52
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Spectroscopic and Theoretical Studies of Dual Fluorescence in 2-Hydroxy-N-(2-phenylethyl)benzamide Induced by ESIPT Process – Solvent Effects
摘要： This work discusses the theoretical ([TD]DFT) and spectroscopic investigation into 2-Hydroxy-N-(2-phenylethyl)benzamide (SAL3) and its physiochemical behaviour in the selected organic solvents. The compound demonstrated a dual fluorescence effect in alcoholic solutions (methanol, ethanol, isopropanol), while in acetonitrile (ACN), dimethylsulfoxide (DMSO) and non-polar solvents (n-Hexane, n-Heptane, chloroform) only a single emission maximum was observed. The noticeable shortening of average fluorescence lifetime, the employed detailed analysis of solvatochromic shifts of absorption spectra in the function of polarizability related to a change in the induction polarization of the environment and, above all, the performed quantum-mechanical calculations [TD] DFT with a detailed analysis of excited states, clearly indicate a connection between the observed fluorescence effects and processes related to changes in the system’s structure in the excited state. Based on these experimental and theoretical studies, it has been proposed that the environment (solvent) polarity-induced dual fluorescence effect in SAL3 is related to the Excited-State Intramolecular Proton Transfer (ESIPT) process. Also, the quantum-mechanic studies [TD] DFT point to the specific conformation of SAL3 molecule characteristic of dual fluorescence emission.
关键词： dual fluorescence effect,salicylic acid derivatives,[TD] DFT calculations,molecular spectroscopy,H-bonds
更新于2025-09-23 15:23:52
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Synthesis, crystal structure, vibrational and optical properties of a new Bi(III) halide complex: (C9H13N2O2)2Bi2Cl8
摘要： A new Bi(III) halide complex, (C9H13N2O2)2Bi2Cl8, was successfully grown by slow evaporation method. The structure of this hybrid compound was determinated by single crystal X-ray diffraction and further characterized by IR and RAMAN spectra, UV-Visible, luminescence and DFT calculations. This compound crystallizes in the monoclinic system P21/n space group with the following lattice parameters: a = 10.2036 (4), b = 9.8723 (4), c = 14.5920 (6) ?, ? = 99.899 (4)°, V = 1448.01 (10) ?3 and Z =2. The crystal structure of this compound was solved by direct methods and refined to R = 0.038 (wR = 0.079), based on 4118 unique observed reflections. The crystal structure consists of a 1-(2-furoyl)piperazinium cation and discrete (0D) anion built up of edge-sharing bioctahedra which are linked by bifurcated N-H…Cl and N-H…O hydrogen bonds to build up the whole molecular packing. The optical properties of this compound were studied by UV–Vis, luminescence spectroscopy and by Time Dependent Density Functional Theory studies. The vibrational properties of this compound were investigated by Infrared and Raman spectroscopy and compared with the calculated ones. The nature and amount of contacts in the crystal packing were investigated by means the Hirshfeld surfaces. Ab-initio and DFT calculations were also performed on whole compound and on reduced model: bis(μ2-chloro)-diaqua-hexachloro-di-bismuth.
关键词： luminescence,X-Ray diffraction,Vibrational studies,Bismuthates,DFT calculations
更新于2025-09-23 15:23:52
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Investigations on the quantum chemical studies and physico-chemical properties of an opto-electronic material 1-Allyl-2-Aminopyridine-1-ium bromide
摘要： In the present work, the dual approach of quantum chemical studies and experimental characterizations of the title compound 1-Allyl-2-Aminopyridine-1-ium bromide (1A2APB) were carried out for the first time. The molecular geometry of 1A2APB was optimized by density functional theory (DFT) using B3LYP/6-311++G (d,p) basis set. The optimized geometric structural parameters were compared with the experimental findings and discussed. The dipole moment (μ) and first hyperpolarizability (β) were calculated to predict the NLO behavior. The frontier molecular orbital (FMO), molecular electrostatic potential (MESP), Mulliken atomic charge and thermodynamic properties were investigated to get a better insight of the molecular properties. Stability of the compound arising from hyper-conjugative interactions, intra-molecule re-hybridization and charge delocalization within the molecule were analyzed using NBO analysis. Further, 1A2APB was synthesized and good quality single crystals were grown by slow evaporation technique. Studies such as microanalysis and powder XRD were performed to ascertain material composition and phase respectively. The various characteristic functional groups were identified through FT-IR spectroscopic analyses. The NLO efficiency was measured to be about greater than 5 times that of standard KDP. Thermal behaviors were explored by the simultaneous TG/DTA-DSC thermograms. The UV–Vis–NIR spectral data and fluorescence spectrum were recorded to explore the optical transmission and emission properties respectively. The dielectric properties were evaluated as a function of frequency at various temperatures. The photoconducting nature was analyzed through photoconductivity measurement. The Vicker’s microhardness test was performed at room temperature from which the mechanical stability was analyzed through the classical Meyer’s relation.
关键词： Photoconductivity,Powder XRD analysis,DFT calculations,Organic materials,Non-linear optics,Crystal growth
更新于2025-09-23 15:23:52
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Synthesis, characterization and DFT analysis of new phthalocyanine complexes containing sulfur rich substituents
摘要： Nine new tetrasubstituted metallophthalocyanines (MPc) bearing sulfur rich substituents on peripheral positions were synthesized and fully characterized. The new MPc compounds contain Co2+, Ni2+ and Cu2+. The photochemical and electrochemical properties of the new molecules were investigated. In addition to this investigation, a comparative study took place on the effect of the type of terminal ligand on properties of the MPc compound. Theoretical studies (DFT) were, also carried out in order to support the corresponding experimental results.
关键词： Cobalt,Copper,Nickel,Microwave synthesis,Phthalocyanines,DFT calculations
更新于2025-09-23 15:23:52