Ultralow voltage imprinting in GeS2–Ga2S3–AgI glasses for visible to middle-infrared diffraction gratings

A diffractive optical element (DOE) covering visible to middle-infrared regions is imprinted in chalcohalide glass by microthermal poling under ultralow voltages (~125 V). The effect of the poling voltage on the surface profiling, optical diffraction, optical transmittance, and anode-side structural rearrangement is investigated. Deformation of the surface profiling and diffraction order increase with increasing poling voltage, showing a saturation voltage of 125 V and a decrease in the transmittance within 10%. In addition to the normal vertical migration of silver ions, an obvious and unexpected transverse migration of silver ions and mutual structural transformation occur between homopolar bonds Ge–Ge (Ga–Ga) and S–S and the heteropolar bond Ge–S (Ga–S), which are key to forming the surface profiling and subsurface structures. Formation of the DOE mainly depends on the periodic subsurface microstructure rather than surface profiling. Thus, simple and inexpensive processes can fabricate broadband wavelength-based DOEs for military, medical and biological applications.     

Influence of NaX (X=Cl,Br, I) additive on phase composition,thermostability and high infrared performances of γ-La2S3 transparent ceramics

A simple method to synthesize Na⁺-doped La₂S₃ powder with only γ phase was developed where NaX (X = Cl, Br, I) served as sodium source. In initial molar ratio Na/La ≥ 0.8 of the mixed raw materials, γ-La₂S₃:Na⁺ tended to reach a constant ratio Na/La = 0.2 and could be represented as Na_0.5La_2.5S₄, which exhibited enough high-temperature stability available for sintering. A modified process was designed to prepare γ-La₂S₃ ceramics with NaCl additive. The microstructure, typical grain boundary composition, photoluminescence and IR performance of as-sintered γ-La₂S₃ ceramics were investigated in details. The optical transparency with mean transmittance 61.3% in 8–14 μm and maximum 64.03% at 13.1 μm was achieved for pellet with Na:La = 0.2 and 1.0 wt% NaCl nanocrystals. NaCl was proved to play multiple roles in governing phase composition, enhancing stability, optimizing microstructure, improving IR properties and affecting luminescence of γ-La₂S₃ ceramics. The mechanisms of action of NaCl additive are proposed by combining the defects reaction, ionic radius and the diffusion behavior of related ions with the cation-deficient structure of γ-La₂S₃.     

新型硫卤玻璃GeS2-Ga2S3-AgX(X=Cl,Br,I)中的K+-Ag+离子交换

以油酸钾为熔盐,GeS2-Ga2S3-AgX(X=Cl,Br,I)玻璃为基玻璃,在270℃的环境温度下,以氮气作为保护气氛,成功地进行了K -Ag 离子交换。在50GeS2-25Ga2S3-25AgI玻璃中,K 离子的交换深度可达256μm,并对交换深度、离子扩散系数以及离子浓度之间的规律进行了初步研究。通过离子交换研究,为制备硫卤玻璃光波导奠定了基础,并可以进一步拓宽硫卤玻璃的应用前景。     

Chemical modification of diamond surface with X–(C6H4)–COOH (X = F,Cl, Br,I) using benzoyl peroxide

The chemical reactivity of a hydrogenated diamond surface with X–(C₆H₄)–COOH (X = F, Cl, Br, I) when using benzoyl peroxide was investigated in this study. After the reaction processes the shapes of the IR spectra changed. It was confirmed from the XPS measurements that halogen atoms existed on the samples after the reaction process. The position of the IR peak at ca. 700 cm^? 1 depended on the kind of halogen in X–(C₆H₄)–COOH. Moreover, the peak position depended on the kind of constitutional isomer, that is, ortho-, meta-, or para-. It was confirmed from the experimental results of this study that halogen-containing organic functional groups can be introduced onto a diamond surface.     

Ho~(3+)/Yb~(3+)共掺TeO_2-ZnO-ZnX_2(X=F,Cl,Br)玻璃的结构和红外发光特性(英文)

采用熔融法制备TeO2-ZnO-ZnX2(X=F,Cl,Br)系统氧卤玻璃块体,并测定了玻璃的各项特征温度。通过Raman光谱和X射线光电子能谱分析了卤化物的引入对玻璃网络结构稳定性的影响。结果表明,加入ZnF2比加入ZnCl2或ZnBr2对Ho3+/Yb3+共掺的碲酸盐玻璃的近红外荧光输出有更明显的效果和规律性。与加入ZnCl2和ZnBr2相比,加入ZnF2对Ho3+/Yb3+共掺的碲酸盐玻璃近中红外的荧光输出影响更加明显和规律。ZnF2虽会抑制1μm处发光但能增强1.2和2μm的发光,同时2μm处荧光输出的量子效率也得到大幅提升。比起使用ZnBr2,使用ZnF2和ZnCl2替代ZnO能更好地提高玻璃的光学性能和热稳定性。在这3种卤化锌中,氟化锌对稀土发光的增强起着更为重要的作用。     

Structural–chemical features and mechanism of crystallization of TlAsX<Subscript>2</Subscript> glasses (X = S,Se)

The vibrational IR spectra of polymer-chain glasses and single crystals of TlAsX₂ (X = S, Se) have been studied. The results of the kinetic study of the surface isothermal crystallization of glasses are theoretically anlayzed in different ways, taking into account the peculiarities of their structure. The semiempirical calculation of the temperature dependence of nonreconstructive crystal growth rate is performed. It is shown that the layered stationary growth of crystals in the TlAsS₂ glass occurs on screw dislocations. In the TlAsSe₂ glass the transition from a dislocation mechanism to two-dimensional nucleation and the layered growth of crystals is possible at supercooling of more than 120°C.     

Theoretical investigation of mixed-ligand lanthanocene complexes, (η5-C5H5)2LnX · OC4H8 (Ln=La,Gd, Lu; X=F,Cl, Br,I)

For the first time, density functional theory (DFT) calculation was performed on the titled complexes and the calculated geometries are in good agreement with the available experimental data. The decrease in the bond distances (Ln–X) as well as the increase in the Hirshfeld charges and the chemical hardness from La to Lu indicates an increase in ionic character on going from La to Lu. The lanthanide contraction and ionic character of metal–ligand bond are found to follow the order: Ln–X > Ln–Cp > Ln–O.     

Rapid phosphorus–nitrogen bond cleavage in bis(diphenylphosphino)amine. Synthesis,X-ray structure and electrochemical characterization of [Ni2(μ2-Ph2P)(μ2-Ph2PNHPPh)2(CNR)2]X,R=Me,n-Bu,Xylyl; X=Cl,I, BPh4 binuclear Ni(I) complexes

Ni(II) reacts with Ni(0) complexes in toluene solution to yield diamagnetic phosphido-bridging Ni(I)–Ni(I) complexes of the type Ni₂(μ²-PPh₂)(CNR)₂(μ²-dppa)₂. The great thermodynamic stability of these complexes is discussed on the light of their electrochemical properties. The X-ray crystal structure of the complexes Ni₂(μ²-PPh₂)(CNR)₂(μ²-dppa)₂, R=n-Bu, Xylyl is also presented.     

An ab initio study on properties of cationic chalcogen bonds in XF2Y+⋯NCZ (X═H,CN, F; Y═S,Se; Z═H,Cl, Br) complexes

The geometries, interaction energies, and bonding properties of cationic chalcogen bonds are studied in binary complexes XF₂Y⁺?NCZ (X═H, CN, F; Y═S, Se; Z═H, Cl, Br). The nature of these interactions is studied by a vast number of methods, including molecular electrostatic potential (MEP), Noncovalent Interaction Index (NCI), quantum theory of atoms in molecules (QTAIM), and natural bond orbital (NBO) analyses. The interaction energies of these complexes vary between ?20.94?kcal/mol in HF₂S⁺?NCH and ?33.72?kcal/mol in F₃Se⁺?NCBr. According to the QTAIM analysis, all these cationic chalcogen bonds are classified as a closed-shell interaction with a partial covalent character. Moreover, cooperative effects between cationic chalcogen bond and hydrogen or halogen bond interactions are studied in ternary XF₂Y⁺?NCZ?NH₃ complexes. These cooperative effects are analyzed in terms of the parameters derived from the QTAIM and NBO analyses, and electron density difference plots.     

Synthesis and characterization of the first [Q]+[PhTeX4]− complex salt (Q=2-Br–C5NH5; Ph=C6H5; X=Br,I) exhibiting a polymeric chain structure

The reaction of diphenylditelluride with 2-bromopyridine in hydrobromide or hydroiodide acid affords the tetrahalophenyltellurate(IV) [2-Br–C₅NH₅][PhTeX₄] (X=Br and I). The structures of the two salts were characterised by single crystal X-ray diffractometry. The anionic units show a square pyramidal geometry about the tellurium atoms with the phenyl rings in the apical positions. Secondary, interanionic Te⋯X bonds as well as cation–anion H–X interactions hold the moieties in polymeric chains with an octahedral configuration about each tellurium center along the crystal lattice.