Neighboring Ions Research Articles

Syntheses and structures of two coordination polymers formed by Ni(cyclam)2+ cations and sulfate anions

The asymmetric units of catena-poly[[(1,4,8,11-tetraazacyclotetradecane-κ4 N 1,N 4,N 8,N 11)nickel(II)]-μ2-sulfato-κ2 O 3:O 4], [Ni(SO4)(C10H24N4)] n (I), and catena-poly[[(1,4,8,11-tetraazacyclotetradecane-κ4 N 1,N 4,N 8,N 11)nickel(II)]-μ2-sulfato-κ2 O 3:O 4] hemi[4,4′,4′′,4′′′-(2,2′,4,4′,6,6′-hexamethyl-[1,1′-biphenyl]-3,3′,5,5′-tetrayl)tetrabenzoic acid] nonahydrate], {[Ni(SO4)(C10H24N4)]2·C46H38O8·18H2O} n (II), consist of two crystallographically unique centrosymmetric macrocyclic dications and a sulfate dianion. In II it includes additionally a molecule of the undissociated acid (2,2′,4,4′,6,6′-hexamethyl[1,1′-biphenyl]-3,3′,5,5′-tetrayl)tetra(benzoic acid) located on a crystallographic twofold axis and nine highly disordered water molecules of crystallization. In both compounds, the metal ions are coordinated in the equatorial plane by the four secondary N atoms of the macrocyclic ligand, which adopts the most energetically stable trans-III conformation. Two O atoms of the sulfate anions occupy the trans-axial positions resulting in a slightly tetragonally distorted trans-NiN4O2 octahedral coordination geometry. The crystals of both compounds are composed of parallel coordination polymeric chains running along the [101] and [100] directions in I and II, respectively. The distances between the neighboring metal ions in the chains are significantly different [6.5121 (6) Å in I and 6.0649 (3) Å in II] and this peculiarity is explained by the different spatial directivity of the Ni—O coordination bonds (different S—O—Ni angles). As a result of the C—H...O hydrogen bonds between the methylene groups of the macrocyclic ligands and the non-coordinated O atoms of the sulfate anion, the coordination-polymeric chains in I are arranged in the two-dimensional layers oriented parallel to the (010) and (101) planes, the intersection of which provides the three-dimensional coherence of the crystals. The three-dimensional supramolecular structure of the crystals II is determined by the network of strong hydrogen bonds formed by the carboxylic acid and the non-coordinated O atoms of the sulfate anions.

An efficient red phosphor LuNb2VO9:Eu3+ with broadband excitation and abnormal thermal quenching properties for personal identification, security ink, and w-LEDs

A series of red-emitting phosphors LuNb2VO9 (LNV):xEu3+ (x = 0.5–45 mol%) were successfully obtained through the high-temperature solid-state reaction. The structure, phase purity, photoluminescence spectra, thermal stability properties, and color purity of the obtained phosphors were systematically examined. The LNV:Eu3+ phosphor exhibits broadband excitation due to the O2-→Eu3+ and O2-→V5+ charge transfer. The LNV:Eu3+ phosphor excited at 316 nm shows four emission peaks at 595, 615, 619, and 699 nm, corresponding to electron transitions from the 5D0 level to the 7F1, 7F2, 7F3 and 7F4 levels. The optimal doped concentration of LNV:xEu3+ is x = 10 mol%. The quenching mechanism is attributed to the nearest neighbor ion interaction. Furthermore, the prepared phosphor exhibits good thermal stability and remarkable activation energy Ea (0.74 eV). In addition, LNV:Eu3+@oleic acid (OA) readily exhibits the level I-III characteristics of fingerprints and the detailed characteristics of lip lines. The successful utilization of LNV:Eu3+ in anti-counterfeiting ink has yielded impressive results. The Commission International de L′ Eclairage (CIE) coordinate of the prepared white light-emitting diode (w-LED) in this study is (0.331, 0.367), accompanied by a color rendering index (Ra) of up to 95. Notably, the results of these experiments indicate that LNV:Eu3+ phosphor possesses exceptional luminescence properties and holds promising applications.

Synthesis, optical properties, and applications of Eu3+, Na+-doped high-color-purity Sr3MgNb2O9 red phosphors for w-LEDs and the detection of latent fingerprints

A series of novel phosphors, doping Eu3+ and Na+ ions in the Sr3MgNb2O9 (SMNO) crystal lattice (SMNO:xEu3+, xNa+, x = 0.5–30 mol%), was successfully synthesized through high-temperature solid-state reaction. X-ray diffraction (XRD) analysis and Rietveld refinement confirmed the successful synthesis of SMNO:Eu3+, Na+. The phosphor belongs to the hexagonal crystal system and the P3¯m1 (No.164) space group. The bandgap energy of SMNO was calculated with Materials Studio and measured with the use of diffuse reflectance spectroscopy. The excitation spectrum of SMNO:Eu3+, Na+ displays multiple narrow absorption peaks in the violet-blue region as well as a charge transfer band (CTB) near 300 nm, exhibiting the highest peak at 394 nm. Four distinct characteristic peaks are observed in the emission spectrum of SMNO:Eu3+, Na+. Notably, the peak at 601 nm shows the highest emission intensity due to the radiative transition from 5D0→7F2. By varying doping concentrations, it was determined that an optimal concentration of 5 mol%Eu3+ resulted in phosphors, with high color purity exceeding 99 %. Concentration quenching is attributed to the nearest neighbor ions interaction. Furthermore, SMNO:Eu3+, Na+ exhibited good stability in 300–480 K, with luminescent intensity remaining 68.6 % at 420 K and 54.4 % at 480 K compared to room temperature (300 K). The internal quantum efficiency (IQE) of SMNO:5%Eu3+, 5 %Na+ is 65.0 %. Both red and white light-emitting diodes (LEDs) were prepared using SMNO:Eu3+, Na+. The chromaticity coordinates of w-LED were measured as (0.357, 0.376), correlating to a correlated color temperature (CCT) of 4685 K and exhibiting a good color rendering index (CRI, Ra = 88). Additionally, the latent fingerprint (LFP) development demonstrated clear visualization of Levels I-III characteristic structures of fingerprints when utilizing SMNO:Eu3+, Na+. These findings suggest promising applications for SMNO:Eu3+, Na+ in w-LED lighting and LFP development.

Effect of Rh Doping on Optical Absorption and Oxygen Evolution Reaction Activity on BaTiO3 (001) Surfaces.

In the present work, we investigate the potential of modified barium titanate (BaTiO3), an inexpensive perovskite oxide derived from earth-abundant precursors, for developing efficient water oxidation electrocatalysts using first-principles calculations. Based on our calculations, Rh doping is a way of making BaTiO3 absorb more light and have less overpotential needed for water to oxidize. It has been shown that a TiO2-terminated BaTiO3 (001) surface is more promising from the point of view of its use as a catalyst. Rh doping expands the spectrum of absorbed light to the entire visible range. The aqueous environment significantly affects the ability of Rh-doped BaTiO3 to absorb solar radiation. After Ti→Rh replacement, the doping ion can take over part of the electron density from neighboring oxygen ions. As a result, during the water oxidation reaction, rhodium ions can be in an intermediate oxidation state between 3+ and 4+. This affects the adsorption energy of reaction intermediates on the catalyst's surface, reducing the overpotential value.

Luminescence and Electron–Hole-Trapping Centers in α-Ca2P2O7−Mn

The mechanisms of formation of induced intrinsic and impurity radiative states, which consist of intrinsic and impurity electron–hole-trapping center states in irradiated Ca2P2O7−Mn and Ca2P2O7 phosphates, were investigated using thermoactivation and vacuum-ultraviolet spectroscopy methods. These centers are excited at photon energies of 4.0 eV and 4.5 eV, which are within the matrix’s transparency region. New radiative-induced states at 3.06 eV and 2.92 eV are demonstrated to be generated upon the excitation of anions by photons with energies of 5.0 and 5.64 eV. This process is due to charge transfer from the ion to the impurities, specifically Mn2+(O2−−Mn2+) and the neighboring ion O 2−−(P2O7)4−. Furthermore, upon the excitation of matrix anions with photon energies exceeding the band gap (8.0–8.25 eV), electron-trapping by impurities such as Mn2+ and (P2O7)4− ions results.

Investigation of the luminescence properties and temperature dependent luminescence properties of Sm3+ doped NaPbBi2(PO4)3 orthophosphate phosphor: A promising candidate for light and light sensing applications

The red phosphor for light application is in high demand. In this regard, a series of orange-red phosphors, NaPbBi2(PO4)3: Sm3+, with a single phase were obtained by the conventional solid state reaction method. The X-ray diffraction (XRD) confirms that the phosphor belongs to the cubic structure with a space group I-43d (220). The optical property of the phosphor was studied through the diffuse reflectance spectroscopy measurements and the characteristic peaks of the Sm3+ ions were identified. Exciting the phosphors at 404 nm, produced a strong orange-red emission at 601 nm. The optimum concentration of the phosphor was found to be 0.03 mol. In all emission transitions of the Sm3+ ions within the host lattice, the energy transfer (ET) occurs among the nearest neighbour ions. The lifetime values were in the order of milliseconds. The photometric parameters revealed that the emission lies in the orange-red region with color coordinates (0.5863, 0.4129) and a color purity of 99.4 %. The temperature dependent luminescence properties of the phosphor were also investigated and all these results showed that the phosphor could serve as a good candidate for light/light sensing applications.

Crystal structure of the sodium salt of mesotrione: a triketone herbicide

The crystal structure of the sodium salt of mesotrione, namely, catena-poly[[sodium-μ3-2-[(4-methanesulfonyl-2-nitrophenyl)carbonyl]-3-oxocyclohex-1-en-1-olato] ethanol monosolvate], {[Na(C14H12NO7S)]C2H5OH} n , is described. The X-ray structural analysis results reveal that the coordination sphere is established by two chelating O atoms, the O atom of the coordinated ethanol molecule, and an O atom from the methylsulfonyl group of a neighboring molecule. Simultaneously, an O atom of the cyclohexane fragment serves as a bridge to a neighboring sodium ion, forming a flat Na–O–Na–O quadrangle, thereby forming a mono-periodic polymer. The structure displays O—H...O hydrogen bonds and C—H...O short contacts. Thermogravimetric analysis (TGA) data indicate that the sodium salt of mesotrione decomposes in four stages.

Factors Affecting Microscopic Basicity of Silicate Glasses from the Perspective of O1s Binding Energy

The factor affecting the microscopic basicity of oxygen in the SiOSi bond are investigated on the basis of the O1s binding energy measured by X‐ray photoelectron spectroscopy (XPS). The samples used are SiO2, Na2OSiO2, CaOSiO2, CaOMgOSiO2, and CaOAl2O3SiO2. For analysis on clean surfaces, samples are finally prepared by fracturing in a vacuum in an XPS system. From the O1s spectra, derived are the centers of gravity of the O1s spectra and the binding energies of O1s in the SiOSi, SiOAl, AlOAl, SiONa, SiOCa, and SiOMg bonds. A good linear relationship is found between the center of gravity of the O1s spectra and the optical basicity, suggesting that the center of gravity of the O1s spectra is a reasonable basicity index of silicate glasses used in this work. It is also found that there is a linear relationship between the binding energy of O1s in the SiOSi bond and the optical basicity, irrespective of the glass systems. This indicates that the experimental microscopic basicity of oxygen in SiOSi bond is affected not only by the first neighboring ions of oxygen but also by the composition of the sample.

Exploring luminescent color tunability and efficient energy transfer mechanism of a single-phased hexagonal nanophosphor for white light emitting diodes (WLEDs) application

Nowadays, NUV-triggered phosphor-converted white light-emitting diodes (pc-WLEDs) have gained prominence as substantial alternatives to conventional incandescent and fluorescent lamps as a source of illumination. In this study, we have successfully developed a Tm3+ codoped La2O3:Sm3+ nanophosphor and investigated its potential suitability for application in white light-emitting diodes (WLEDs). X-ray diffraction (XRD) analysis was conducted to examine the phase impurity and structural characteristics of the synthesized nanophosphor. The analysis confirmed the formation of a single-phase La2O3 nanophosphor with a hexagonal crystal structure. The FT-IR spectrum of the synthesized nanophosphor exhibited distinct peaks associated with the vibrational frequencies of La-O bonds. The peaks observed in the fingerprint region of the spectrum, indicate the presence of La-O atoms in the nanophosphor. However, the HR-TEM analysis confirmed that the prepared nanophosphor had a polycrystalline nature and the observed particle sizes lay within the nanoscale range. The incorporation of Tm3+ ions into the host matrix led to a reduction in the optical band gap, leading to enhanced emission intensity. The photoluminescence (PL) study reveals that the Tm3+ ion exhibited blue emission upon excitation at 360 nm, whereas the Sm3+ ion emits reddish-orange light when excited at 379 nm and 408 nm, respectively. However, under 325 nm excitation, the nanophosphor exhibited a white emission color that resulted from the blending of colors emitted by both Tm3+ and Sm3+ ions. This unique finding suggests that this nanophosphor has the potential to generate white light specifically under this particular excitation wavelength. The efficient energy transfer between Tm3+ and Sm3+ ions was attributed to the electric multipolar interaction between the nearest neighbor ions, leading to a quenching phenomenon. Furthermore, the photometric analysis revealed that the correlated color temperatures (CCTs) associated with the emitted white light were found to be higher than 4000 K. Thus, based on these characteristics, it can be inferred that the prepared nanophosphor has the potential to be utilized as a cool white-emitting nanophosphor for single-phased WLEDs application.

Theoretical Investigation of Pressure Dependent Structural and Elastic Properties of MnSi Compound

MnSi is a metallic compound that exhibits a structural phase transition as a function of pressure. At ambient conditions, MnSi has a cubic structure such as NaCl type crystal structure. However, at high pressures, it undergoes a structural phase transition to a CsCl type crystal structure. The pressure-dependent structural phase transition in MnSi has been studied using various experimental and theoretical techniques. In the present work, we have used an efficient inter-ionic potential approach to predict pressure dependent structural phase change and associated volume collapse in MnSi. Therein, the potential includes the long-range Coulomb, van der Waals (vdW) interaction, and the short-range repulsive interaction up to second neighbour ions. It has been demonstrated that the Hafemeister and Flygare approach successfully evaluates the equation of state for change in volume with respect to applied pressure. We have identified a structural phase transition from B1(NaCl) type structure to B2 (CsCl) type structure in this compound. The estimated value of phase transition pressure (Pt) is 42 GPa, which is consistent with the available reported data. The identified first order phase transformation showed a volume collapse of about 10% in the vicinity of transition. In addition, we have also investigated second order of elastic constants for MnSi compound.

Study of hydrogen exchange between the Zr–1%Nb alloy and the gaseous ambient through the oxidized surface under ion and atomic irradiation

In the article, a hydrogen exchange between the Zr–1%Nb alloy (E110) and the gas ambient was experimentally studied when the samples were irradiated with deuterium and argon plasma ions. It has been established that, upon irradiation with deuterium plasma ions with an energy of E = 650 eV/at, the enhanced absorption of deuterium exceeds the release of hydrogen initially contained in the samples, which leads to their loading with hydrogen isotopes. Adding 30 at.% oxygen to the plasma-forming gas or raising the sample temperature from T = 450 K to T = 600 K, significantly reduces the content of hydrogen isotopes in the sample. Based on the aggregate data obtained by atomic and ion irradiation, a mechanism of hydrogen exchange between zirconium alloy and gas ambient is proposed. The process includes three stages: reactions on the oxidized surface of the zirconium alloy (surface hydroxylation and formation of water molecules); reactions at the metal-oxide interface; transfer of hydrogen isotopes through the surface oxide layer in both directions due to hopping between neighboring oxygen ions. Surface reactions caused by irradiation of atoms and ions trigger the hydrogen exchange. The proposed model agrees with the experimental data on the irradiation of the E110 alloy with atoms and ions of hydrogen isotopes.

Revealing the two-body ring-breaking dynamics of benzene in the (C6H6)2, C6H6Ar, and C6H6Kr dimers

The ring-breaking dynamics of ${\mathrm{C}}_{6}{\mathrm{H}}_{6}$ in its three dimers $[{({\mathrm{C}}_{6}{\mathrm{H}}_{6})}_{2},$ ${\mathrm{C}}_{6}{\mathrm{H}}_{6}\mathrm{Ar},$ and ${\mathrm{C}}_{6}{\mathrm{H}}_{6}\mathrm{Kr}]$ are investigated by performing three-body coincidence measurements after interaction with a strong femtosecond laser. The measurements enabled the observation of three ring-breaking channels, resulting in products of ${\mathrm{C}}_{1}{\mathrm{H}}_{3}^{+}+{\mathrm{C}}_{5}{\mathrm{H}}_{3}^{+},$ ${\mathrm{C}}_{2}{\mathrm{H}}_{3}^{+}+{\mathrm{C}}_{4}{\mathrm{H}}_{3}^{+},$ and ${\mathrm{C}}_{3}{\mathrm{H}}_{3}^{+}+{\mathrm{C}}_{3}{\mathrm{H}}_{3}^{+}$ with the neighbor ions. Additionally, kinetic energies from intra- and intermolecular fragmentation are extracted. By using the neighbor ion as a reference, it is found that the lifetimes of corresponding dissociation states have a significant impact on the final angular distributions of the fragments. The vibration excitation of molecules induced by neighboring ions during the repelling process alters the relative ratio between the three observed ring-breaking channels. By examining the ring-breaking dynamics of aromatic molecules in different environments, this study provides valuable insights into molecular fragmentation in complex systems.

Taming Super-Reduced Bi23- Radicals with Rare Earth Cations.

Here, we report the synthesis of two new sets of dibismuth-bridged rare earth molecules. The first series contains a bridging diamagnetic Bi22- anion, (Cp*2RE)2(μ-η2:η2-Bi2), 1-RE (where Cp* = pentamethylcyclopentadienyl; RE = Gd (1-Gd), Tb (1-Tb), Dy (1-Dy), Y (1-Y)), while the second series comprises the first Bi23- radical-containing complexes for any d- or f-block metal ions, [K(crypt-222)][(Cp*2RE)2(μ-η2:η2-Bi2•)]·2THF (2-RE, RE = Gd (2-Gd), Tb (2-Tb), Dy (2-Dy), Y (2-Y); crypt-222 = 2.2.2-cryptand), which were obtained from one-electron reduction of 1-RE with KC8. The Bi23- radical-bridged terbium and dysprosium congeners, 2-Tb and 2-Dy, are single-molecule magnets with magnetic hysteresis. We investigate the nature of the unprecedented lanthanide-bismuth and bismuth-bismuth bonding and their roles in magnetic communication between paramagnetic metal centers, through single-crystal X-ray diffraction, ultraviolet-visible/near-infrared (UV-vis/NIR) spectroscopy, SQUID magnetometry, DFT and multiconfigurational ab initio calculations. We find a πz* ground SOMO for Bi23-, which has isotropic spin-spin exchange coupling with neighboring metal ions of ca. -20 cm-1; however, the exchange coupling is strongly augmented by orbitally dependent terms in the anisotropic cases of 2-Tb and 2-Dy. As the first examples of p-block radicals beneath the second row bridging any metal ions, these studies have important ramifications for single-molecule magnetism, main group element, rare earth metal, and coordination chemistry at large.

Using energy transfer to obtain warm white-emitting and thermally stable Ca3Y(AlO)3(BO3)4:Dy3+, Eu3+ phosphors

A series of color-tunable warm white-emitting phosphors Ca3Y(AlO)3(BO3)4:Dy3+,Eu3+ were synthesized and characterized for their crystal structure, luminescence properties, thermal stability, fluorescence decay and energy transfer mechanism. The results show that the optimal excitation wavelength and doping concentration of Ca3Y(AlO)3(BO3)4:Dy3+ phosphor are 350 nm and 0.05 mol%, respectively, and its concentration quenching is mainly caused by the interaction between nearest neighbor ions. Under the excitation at 350 nm, the Ca3Y(AlO)3(BO3)4:Dy3+,Eu3+ phosphor showed prominent emission peaks at 471 nm, 576 nm and 622 nm. The photoluminescence spectrum and lifetime decay curves confirmed the presence of Dy3+→Eu3+ energy transfer in Ca3Y(AlO)3(BO3)4. The phosphor of Ca3Y0·85(AlO)3(BO3)4:0.05Dy3+,0.1Eu3+ exhibited remarkable thermal stability and could maintain 87.68% of the emission intensity at 150 °C. By adjusting the doping ratio of Dy3+ and Eu3+ ions, the CIE coordinates and the related color temperature of Ca3Y(AlO)3(BO3)4:Dy3+,Eu3+ phosphors can be adjusted. The w-LED device packaged with Ca3Y0·85(AlO)3(BO3)4:0.05Dy3+,0.1Eu3+ phosphor can emit warm-white light (Tc = 3284 K, Ra = 72.7). These results suggest that Ca3Y(AlO)3(BO3)4:Dy3+,Eu3+ phosphor can provide a potential alternative for the warm w-LED market.

Tuning Discharge Behavior of Hollandite α-MnO2 in Hydrated Zinc Ion Battery by Transition Metal Substitution

The tunnel-type hollandite α-MnO2 is a promising cathode material for rechargeable aqueous zinc-ion batteries (ZIBs) due to its low cost in synthesis and high energy density. However, irreversible structural degradation upon continuous cycling prevents the cathode from being utilized commercially. Herein, density functional theory (DFT) was utilized to conduct a systematic study on tuning the behavior of α-MnO2 by substituting the Mn ions on the tunnel wall with a transition metal (V or Cr) during the H+-/Zn2+-intercalation in hydrated ZIB. Our study revealed that both substituents aid cyclability and capacity retention with Cr outperforming V. In term of discharge voltage, only the Cr-substitution displays clear promotion at the early stage of discharge. The superior performance of substituted Cr4+ comes from its unique atomic and electronic structures. Upon discharge, it can be reduced to Cr3+ more readily than Mn4+ and thereby limits the formation of unstable Mn3+ or Mn2+ centers; the formed Cr3+ is more stable than Mn3+ and Mn2+ from the reduction of Mn4+; and Cr3+ can also greatly stabilize the neighboring Mn ions. This study highlights the significant tuning effect of transition metal substitution on the electrochemical and physical performance of α-MnO2 as a cathode in hydrated ZIBs.

Synthesis and photoluminescence properties of NaYGeO4:Bi3+ phosphors

In this paper, NaYGeO4:[Formula: see text]Bi[Formula: see text] phosphors were successfully prepared by high-temperature solid-state reaction. XRD patterns and refinement results show that Bi[Formula: see text] ions are successfully incorporated into the matrix material and replaced by Y[Formula: see text]. The emission spectrum shows that the optimal doping concentration of the sample is 0.25%, and it is theoretically studied that the concentration quenching is caused by the nearest neighbor ions. The fluorescence lifetime curve showed that with the increase of Bi[Formula: see text] concentration, the fluorescence lifetime first increased and then decreased. The thermal stability of the sample was studied, and it was found that when the temperature increased to 523 K, the luminescence intensity of the phosphor was still 70% of the initial intensity, and the activation energy was calculated to be 0.306 eV. Finally, the CIE color coordinates of the sample with the best luminous intensity were calculated as (0.1595, 0.0342), and the color coordinates are located in the blue light region.

Comprehensive investigation of Er2O3 thin films grown with different ALD approaches

The effect of Er precursor nature (Er(CpMe)3 or Er(tmhd)3) and annealing treatment at 500–1100 °C on the structural and optical properties of Er2O3 films grown on Si substrates by thermal or O2-plasma-assisted atomic layer deposition was studied by means of spectroscopic ellipsometry, Fourier-transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy coupled with energy dispersive X-ray spectroscopy as well as photoluminescence method. An annealing at 500–800 °C resulted in the film crystallization mainly. Thermal treatment at high temperatures caused the formation of Er silicate phase due to the diffusion of Si atoms from the substrate in the films depth. This phase was found to be Er2SiO5 being crystallized at 1100 °C. Light emitting properties of the films are determined by Er2O3 native defects (like oxygen vacancies) and intra-4f shell transition in Er3+ ions. The latter dominated in the films annealed at 1000–1100 °C. The most intense Er3+ emission, observed in the films grown with O2-plasma-assisted approach, was explained by a lower contribution of oxygen vacancies as well as by pronounced crystallization of Er silicate phase. In this latter, the effect of concentration quenching of Er3+ luminescence was lower due to a larger distance between Er3+ neighbor ions.

Femtosecond Time-Resolved Neighbor Roles in the Fragmentation Dynamics of Molecules in a Dimer.

How the neighbor effect plays its role in the fragmentation of molecular clusters attracts great attention for physicists and chemists. Here, we study this effect in the fragmentation of N_{2}O dimer by performing three-body coincidence measurements on the femtosecond timescale. Rotations of bound N_{2}O^{+} triggered by neutral or ionic neighbors are tracked. The forbidden dissociation path between B^{2}Π and ^{4}Π is opened by the spin-exchange effect due to the existence of neighbor ions, leading to a new channel of N_{2}O^{+}→NO+N^{+} originating from B^{2}Π. The formation and dissociation of the metastable product N_{3}O_{2}^{+} from two ion-molecule reaction channels are tracked in real time, and the corresponding trajectories are captured. Our results demonstrate a significant and promising step towards the understanding of neighbor roles in the reactions within clusters.

Synthesis and characterization of a new double perovskite phosphor: NaCaTiTaO6:Dy3+ with high thermal stability for w-LEDs application

A new yellow-emitting phosphor, NaCaTiTaO6:Dy3+, was synthesized via solid-phase synthesis at 1300 ℃. X-ray diffraction (XRD) analysis and Rietveld refinement showed that the prepared phosphors exhibited a stable double perovskite structure. The particle size of the phosphor was around 3.8 μm. The maximum emission peak at 574 nm is attributed to the 4F9/2→6H13/2 energy level transition under irradiation at 389 nm. The optimum Dy3+ doping concentration is 0.10 M equivalent, and concentration quenching is due to the nearest neighbor ion interaction. The luminescence intensity of the phosphor was reduced by only 15% at 420 K, exhibiting high thermal stability. Quantum yield (QY) was measured to be 26.31%. Finally, the Commission International de I’Eclairage (CIE) color coordinate of the phosphor for white light emitting diode (w-LED) was (0.314, 0.323), with a color rendering index (Ra) of 92 and a correlated color temperature (CCT) of 5578 K. Above all, the Dy3+-doped double perovskite NaCaTiTaO6:Dy3+ phosphor is expected to be used in w-LEDs.

Optical and structural properties of an octupolar salt: Triphenylguanidinium trithiocyanurate

A new triphenylguanidinium salt, triphenylguanidinium trithiocyanurate, has been synthesized and characterized by single-crystal X-ray diffraction revealing a monoclinic centrosymmetric assembling of cations and anions. The crystal structure of title salt contains ribbons propagating along the b axis, assembled by two strong N–H⋯S hydrogen bonds between the neighboring negative ions. The trithiocyanurate ion exhibits a characteristic fingerprint plot, that has been found in similar salts. Hyperpolarizabilities of anions, cations and their neutral cluster were calculated using Density Functional Theory and the functional CAM-B3LYP. Using a combined approach between the supermolecule model and oriented gas model, the predicted third harmonic generation is 40 times that of fused silica.