Synthesis of rare earth sulfides and their UV-vis absorption spectra

Rare earth sulfides were systematically synthesized via the sulfurization of their commercial oxide powders using CS2 gas to shorten sulfurization time, and their UV-vis absorption spectra were investigated. The appropriate sulfurization conditions were studied. For the rare earth sulfides with the same crystal structure, the sulfurization temperature showed increasing tendency with the decrease of rare earth element atomic radii. The UV-vis absorption spectra of rare earth sulfides did not depend on the crystal structure of rare earth sulfides, but on the 4f electronic structure of rare earth element. The data showed that the optical band gaps of rare earth sulfides were irregular, and the values ranged from 1.65 to 3.75 eV.

Contacted Ion Pairs in Aqueous CuCl2 by the Combination of Ratio Spectra, Difference Spectra, Second Order Difference Spectra in the UV-Visible Spectra

The microstructure of aqueous CuCl2 has been studied through lots of technologies for many years; however, it remains a controversial subject. In this study, a new spectroscopic method has been proposed to analyze the UV-visible spectra of thin fihn of CuCl2/H2O solutions at different concentrations. This method is the combination of ratio spectra, difference spectra and second order difference spectra. By using this method, two new bands at -230 and -380 nm are obviously observed. The bands are assigned as the contacted ion pairs [CuCl3（H2O）n]- or [CuCl4（H2O）n]2-, which demonstrates that ion pairs exist in the CuCl2/H2O solution. Such finding agrees with the recent theoretical spectra obtained by time-dependent density functional theory. Furthermore, the populations of the contacted ion pairs are discussed. This study not only offers the direct spectroscopic evidence of [CuCl3（H2O）n]- or [CuCl4（H2O）n]2- in aqueous CuCl2, but also suggests that the spec- troscopic analysis method is powerful to extract the weak bands in a strong overlapping spectrum.

Study on superoxide and hydroxyl radicals generated in indirect electrochemical oxidation by chemiluminescence and UV-Visible spectra

The generation and transformation of radicals on the cathode of indirect electrochemical oxidation were studied by chemilumines- cence(CL)and UV-Visible spectra in the reactor with a salt bridge that connected the separated chambers.The CL intensity of 4×10^(-9)mol/L luminol on the cathode with bubbling oxygen was about seven times that of the intensity without it,which was because of the generation of reactive oxygen species(ROS).The existence of ROS,especially the generation of the superoxide radical,coul...

Synthesis, Crystal Structure, Thermal Stability and Solid UV-Vis Absorption Spectra of One New Copper(Ⅱ) Coordination Polymer

A new coordination polymer [Cu2(OH)(nbta)(tib)(H2 O)2]n(1, H3 nbta = 5-nitro-1,2,3-benzenetricarboxylic acid, tib = 1-(4 H-1,2,4-triazol-4-yl)-4-(imidazol-1-yl)benzene) constructed from dimeric Cu(Ⅱ) units has been synthesized under hydrothermal conditions and structurally characterized by single-crystal X-ray diffraction analysis. The compound crystallizes in monoclinic system, space group I2/c, with a = 17.8474(9), b = 11.7588(6), c = 21.9221(11) ?, β = 104.419(5)°, V = 4455.7(4) ?3 and Z = 8. Compound 1 is a three-dimensional structure constructed from dimeric Cu(Ⅱ) units and presents a 2-nodal(3,5)-connected net. Moreover, the thermal stability and solid UV-Vis absorption spectra have been investigated.

A New Palladium Complex Containing the Mixture of Carbene and Phosphine Ligands: Synthesis, Crystal Structure and Spectral FT-IR, NMR and UV-Vis Researches

In this paper,a new Pd-based complex that contains A^-heterocyclic carbene(NHC)and triphenylphosphine(PPh?)ligands was synthesized.The c/5-(NHC)PdBr2(PPh3)complex has been prepared by the substitution of 3?chloropyridine ligand in(NHC)PdBr2(3-chloropyridine)complex with triphenylphosphine.This complex has been characterized by using 1^H NMR,^31P{^1H}NMR,^13C{^1H}NMR,FTIR,UV-Vis spectroscopy and elemental analysis techniques.The molecular and crystal structures of the cz5-(NHC)PdBr2(PPh3)complex were determined by singlecrystal X-ray diffraction method.

Interaction of 4-aminosalicylic Acid and Surfactants in Aqueous Solutions Using UV-Vis Spectra and Steady-state Fluorescence Spectroscopy

The interactions of 4-aminosalicylic acid （4-ASA） and surfactants in aqueous solutions were investigated by using UV-Vis spectra and steady-state fluorescence spectroscopy.The results showed that the strongest peak at UV-vis spectra of 4-ASA aqueous solution in the presence of cationic surfactant and cetyltrimethyl ammonium bromide （CTAB） appeared at 206 nm and took a red shift from 206 nm to 221 nm with the increase of 4-ASA concentrations from 0.8×10-5 to 4.4×10-4 mol/L.Similarly,the strongest peak at UV-vis spectra of 4-ASA aqueous solution in the presence of nonionic surfactant and polyvinylpyrrolidone （PVP） appeared at 206 nm and took a red shift from 206 nm to 219 nm with the increase of 4-ASA concentrations from 0.8×10-5 to 4.4×10-4 mol/L.However,the similar phenomena did not appeared in the presence of anion surfactant,sodium dodecyl sulfate （SDS）,the UV-vis spectra of 4-ASA aqueous solution remained the same peak position and the peak value increased with the 4-ASA concentration increase.The results could be attributed to the electrostatic attraction between 4-ASA and CTAB or PVP,as well as the electrostatic repulsion between 4-ASA and SDS.Furthermore,the value of critical micelle concentration （CMC） of surfactants in the presence of 4-ASA was determined with Fluorescence method.The first and second CMC of CTAB was 1.2×10-4 M and 2.4×10-4 M,respectively.The first and second CMC of PVP was 1.2×10-4 M and 2.8×10-4 M.SDS realized the multiple micellizations to form multiple CMC.

Experimental and Theoretical Studies on the Molecular Structure, FT-IR and UV-vis Spectra of 1,8-Dihydroxyanthraquinone

In the present work, both experimental and theoretical studies have been performed on the molecular structure and infrared spectra of 1,8-dihydroxyanthraquinone （1,8- DHAQ）. The FT-IR spectra （400--4000 cm1） of 1,8-DHAQ were recorded, while density functional B3LYP calculations were employed in conjunction with the 6-31G（d） and 6-311G（d,p） basis sets to investigate the corresponding geometrical structure and infrared spectroscopic properties. Besides, the detailed interpretations of fundamental vibrations were performed on the basis of the experimental results and potential energy distribution （PED） of the vibrational modes. Optimized structure of the title compound was interpreted and compared with the earlier reported experimental values, which yielded good agreement. The measured and calculated harmonic vibrational wavenumbers were compared with each other, and they were found to be in good accordance. Furthermore, UV-vis spectra of the compound were recorded in the region of 215-500 nm, and it was found that the five intense electronic transitions predicted by the EOM-B3LYP/6-31G（d） method were largely consistent with the measured experimental data in the ethanol solution. Moreover, the calculated HOMO and LUMO energies show charge transfer within the molecule.

Computational Study on UV-Vis and CD Spectra of Chiral Schiff Base Ni（ll）, Cu（ll） and Zn（ll） Complexes for Discussion of Induced CD

Simulated UV-vis and CD （circular dichroism） spectra were obtained for several chiral Schiff base Ni（II）, Cu（II） and Zn（II） complexes by TD-DFT （time dependent-density functional theory）and Z1NDO calculations. Dipole moments for them were also evaluated by ZINDO calculations and revealed that Cu（II） complexes exhibited the largest values than the analogous Ni（II） and Zn（II） complexes. Although these complexes possessed large dipole moments, induced CD by these complexes were observed a Cu（II）-containing metallodendrimer nor Cu-nanoclusters prepared in a PAMAM （polyamidoamine） dendrimer experimentally nevertheless of other related chiral Schiff base Ni（II）, Cu（II）, and Zn（II） complexes. The present results suggested that steric factors of ligands were more important than electronic factors for emerging induced CD bands by supramolecular interactions.

Crystal Growth of Cu6(Ge,Si)6O18·6H2O and Assignment of UV-VIS Spectra in Comparison to Dehydrated Dioptase and Selected Cu(II) Oxo-Compounds Including Cuprates

Low-dimensional quantum spin systems with the Cu2+ central ion are still in the focus of experimental and theoretical research. Here is reported on growth of mm-sized single-crystals of the low-dimensional S = 1/2 spin compound Cu6(Ge,Si)6O18·6H2O by a diffusion technique in aqueous solution. A route to form Si-rich crystals down to possible dioptase, the pure silicate, is discussed. Motivated by previously reported incorrect assignments of UV-VIS spectra, the assignment of dd excitations from such spectra of the hexahydrate and the fully dehydrated compound is proposed in comparison to dioptase and selected Cu(II) oxo-compounds using bond strength considerations. Non-doped cuprates as layer compounds show higher excitation energies than the title compound. However, when the antiferromagnetic interaction energy as Jz·ln(2) is taken into account for cuprates, a single linear relationship between the Dqe excitation energy and equatorial Cu(II)-O bond strength is confirmed for all compounds. A linear representation is also confirmed between 2A1g energies and a function of axial and equatorial Cu-O bond distances if auxiliary axial bonds are used for four-coordinated compounds. The quotient Dt/Ds of experimental orbital energies deviating from the general trend to smaller values indicates the existence of H2O respectively Cl−axial ligands in comparison to oxo-ligands, whereas larger Dt/Dqe values indicate missing axial bonds. The quotient of the excitation energy 2A1g by 2·2Eg-2B2g allows checking for correctness of the assignment and to distinguish between axial oxo-ligands and others like H2O or Cl−.

Deep learning for determining pure isotropic proton spectra from solidstate spectra

Recently,an article on ^(1)H solid-state NMR spectra was published,in which the authors proposed a deep learning approach to infer the pure isotropic proton NMR spectra obtained at an infinite magic angle spinning(MAS)rate.This approach even allowed to obtain,by far,the best resolved ^(1)H spectra of molecular solids[1](https://doi.org/10.1002/anie.202216607).Deep learning based artificial intelligence is developing rapidly,and its application is deepening.Currently,there are many applications of deep learning in the field of magnetic resonance,such as the reconstruction of the under-sampled multidimensional spectra[2-4],the deconvolution of two-dimensional NMR spectra[5]and noise suppression and weak peak retrial[6],etc.

Tunable spectral continuous shift of high-order harmonic generation in atoms by a plasmon-assisted shaping pulse

We delve into the phenomenon of high-order harmonic generation within a helium atom under the influence of a plasmon-assisted shaping pulse.Our findings reveal an intriguing manipulation of the frequency peak position in the harmonic emission by adjusting the absolute phase parameter within the frequency domain of the shaping pulse.This phenomenon holds potential significance for experimental setups necessitating precisely tuned single harmonics.Notably,we observe a modulated shift in the created harmonic photon energy,spanning an impressive range of 1.2 eV.This frequency peak shift is rooted in the asymmetry exhibited by the rising and falling edges of the laser pulse,directly influencing the position of the peak frequency emission.Our study quantifies the dependence of this tuning range and the asymmetry of the laser pulse,offering valuable insights into the underlying mechanisms driving this phenomenon.Furthermore,our investigation uncovers the emergence of semi-integer order harmonics as the phase parameter is altered.We attribute this discovery to the intricate interference between harmonics generated by the primary and secondary return cores.This observation introduces an innovative approach for generating semi-integer order harmonics,thus expanding our understanding of high-order harmonic generation.Ultimately,our work contributes to the broader comprehension of complex phenomena in laser-matter interactions and provides a foundation for harnessing these effects in various applications,particularly those involving precise spectral control and the generation of unique harmonic patterns.

Wavelength calibration and spectral analysis of vacuum ultraviolet spectroscopy in EAST

A vacuum ultraviolet(VUV)spectroscopy with a focal length of 1 m has been engineered specifically for observing edge impurity emissions in Experimental Advanced Superconducting Tokamak(EAST).In this study,wavelength calibration for the VUV spectroscopy is achieved utilizing a zinc lamp.The grating angle and charge-coupled device(CCD)position are carefully calibrated for different wavelength positions.The wavelength calibration of the VUV spectroscopy is crucial for improving the accuracy of impurity spectral data,and is required to identify more impurity spectral lines for impurity transport research.Impurity spectra of EAST plasmas have also been obtained in the wavelength range of 50–300 nm with relatively high spectral resolution.It is found that the impurity emissions in the edge region are still dominated by low-Z impurities,such as carbon,oxygen,and nitrogen,albeit with the application of fulltungsten divertors on the EAST tokamak.

Core level excitation spectra of La and Mn ions in LaMnO3

Manganese-based perovskite is popular for research on ferromagnetic materials,and its spectroscopic studies are essential for understanding its electronic structure,dielectric,electrical,and magnetic properties.In this paper,the M-edge spectra of La ions and the M-edge,L-edge,and K-edge spectra of Mn ions in LaMnO3 are calculated by considering both the free-ion multiplet calculation and the crystal field effects.We analyze spectral shapes,identify peak origins,and estimate the oxidation states of La and Mn ions in LaMnO3 theoretically.It is concluded that La ions in LaMnO3 predominantly exist in the trivalent state,while Mn ions exist primarily in the trivalent state with a minor presence of tetravalent ions.Furthermore,the calculated spectra are in better conformity with the experimental spectra when the proportion of Mn3+is 90%and Mn4+is 10%.This article enhances our comprehension of the oxidation states of La and Mn within the crystal and also provides a valuable guidance for spectroscopic investigations of other manganates.

Discrimination of pressed sesame oil:A comparison study of non-targeted UV spectral fingerprints combined with different chemometric methods

This study explores the utilization of various chemometric analytical methods for determining the quality of pressed sesame oil with different adulteration levels of refined sesame oil using UV spectral fingerprints.The goal of this study was to provide a reliable tool for assessing the quality of sesame oil.The UV spectra of 51 samples of pressed sesame oil and 420 adulterated samples with refined sesame oil were measured in the range of 200-330 nm.Various classification and prediction methods,including linear discrimination analysis(LDA),support vector machines(SVM),soft independent modeling of class analogy(SIMCA),partial least squares regression(PLSR),support vector machine regression(SVR),and back-propagation neural network(BPNN),were employed to analyze the UV spectral data of pressed sesame oil and adulterated sesame oil.The results indicated that SVM outperformed the other classification methods in qualitatively identifying adulterated sesame oil,achieving an accuracy of 96.15%,a sensitivity of 97.87%,and a specificity of 80%.For quantitative analysis,BPNN yielded the best prediction results,with an R^(2) value of 0.99,RMSEP of 2.34%,and RPD value of 10.60(LOD of 8.60%and LOQ of 28.67%).Overall,the developed models exhibited significant potential for rapidly identifying and predicting the quality of sesame oil.

基于荧光光谱和拉曼光谱技术的中药检测研究

中医药是中华文化的瑰宝和中华文明的结晶,在全民健康中发挥着重要作用。由于中药生长环境受限及市场需求量的增大,市场上出现了许多以次充好、以假乱真的中药,这对中药发展及质量保障都极为不利。因此,对中药的检测和鉴定非常重要。为了探究中药的荧光光谱和拉曼光谱特性,选取白芷、苏木、山药、地榆四种中药进行分类检测研究。一方面,从化学成分和结构的角度分析中药白芷和苏木产生荧光的可能性,采用F-4600型荧光光谱仪(200~750 nm)分别在不同激发波长和不同浓度下测试了白芷和苏木水浸液的荧光光谱,探究了白芷和苏木水浸液的荧光光谱特性,并对荧光强度与不同浓度、激发波长的关系进行了探讨。另一方面,采用共聚焦显微拉曼光谱仪(100~4000 cm^(-1))对4种不同产地的山药和2种不同产地的地榆中药饮片的拉曼光谱分别进行测试研究。结果表明,白芷水浸液在波长260~350 nm的光激发下,产生较强荧光,最佳激发波长是340 nm,荧光峰值波长为420 nm,其荧光强度随浓度的增大而增强,且样品浓度较低时,荧光强度与浓度成线性关系;苏木水浸液在200~290 nm的光激发下,产生较强荧光,最佳激发波长为220 nm,荧光峰值波长为345 nm,随浓度的增加,荧光强度先增强后减弱,在浓度为0.175 mg·mL^(-1)时荧光强度达到最大。白芷水浸液和苏木水浸液的荧光强度都与激发波长的关系呈现高斯分布,符合荧光规律。分析山药和地榆的拉曼光谱,发现不同产地的拉曼特征基本一致,确认山药的拉曼特征峰主要集中在477、862、939、1080、1258、1337和1457 cm^(-1)处;地榆的拉曼特征峰主要集中在862和1337 cm^(-1)处,主要归属与已有的化学成分研究结果相符。部分特征峰处拉曼活性出现差异,可以作为区分不同产地中药的依据。该研究结果不仅为荧光光谱在中药鉴定及质量分析中的应用提供了实验数据和方法参考,也为利用拉曼光谱技术实现中药的快速准确检测及产地归属奠定了基础。

氟诺哌齐结构和性质的密度泛函理论研究

氟诺哌齐是一种新型的抗阿尔茨海默病临床候选药物,目前尚处于临床试验阶段;对氟诺哌齐进行密度泛函理论研究,有助于揭示其分子的性质和功能.在B3LYP/6-311+G(d,p)基组水平上,采用密度泛函理论(DFT)的方法优化氟诺哌齐的分子结构;在相同基组水平下经过谐振频率分析,证实了12种分子构象的稳定结构,并确定了优势构型为DC20-1.根据Marcus理论,对其重组能进行模拟计算,得出氟诺哌齐分子不具备运输性质.通过前线轨道(FMO)分析,发现氟诺哌齐分子具有一定的电子跃迁能力和分子内反应活性,活性反应位点为C15、O28、C23和O26.根据红外光谱、紫外-可见吸收光谱模拟计算结果,对谱图数据进行了讨论分析,研究结果可作为氟诺哌齐表征和鉴别的参考依据.

四氮杂芳氧基取代酞菁金属配合物的UV-Vis吸收光谱研究

测定了6个系列18种四氮杂芳氧基取代酞菁金属配合物（R4PCM，R=4-吡啶氧基、8-喹啉氧基、2-甲基-8喹啉氧基；取代位置分别为：α位及β位；M=Ni（Ⅱ），Cu（Ⅱ），Zn（Ⅱ））的UV-Vis吸收光谱。探讨了中心金属、取代基种类及取代位置、溶剂对酞菁金属配合物UV-Vis吸收光谱中Q带最大吸收波长（λmax）的影响，实验结果表明：标题配合物的Q带λmax在680nm左右；与相同中心金属无取代酞菁金属配合物（669～671nm）比较，标题配合物的Q带λmax都发生了不同程度的红移；当取代基在α位时其种类对标题配合物Q带λmax的影响较在β位时显著，且相同取代基及中心金属的α位取代配合物的Q带λmax较β位取代配合物的红移更为明显；中心金属、溶剂对标题配合物的Q带λmax影响不明显。

Cobe Spectra与Fenwal CS 3000 Plus血细胞分离器外周血造血干/祖细胞的采集效能比较

为了评价Cobe Spectra(Version 6.1)和Fenwal CS 3000 Plus两种血细胞分离机在造血干／祖细胞采集中的 采集效能,对36人64次外周血造血干／祖细胞的采集进行了回顾性分析。20人42次使用Cobe Spectra采集,16人 22次使用Fenwal CS 3000 Plus采集。对CD34+细胞采集量、采集效率以及红细胞与血小板的采集量进行比较。结 果表明:Cobe Spectra和Fenwal CS 3000 Plus在CD34+细胞采集量和采集效率上无显著差异。CD34+细胞采集量 与供者白细胞、单核细胞、造血祖细胞、CD34+细胞的动员情况呈正相关,在多因素stepwise线性回归模型中,采集 前外周血干／祖细胞浓度是唯一有意义的影响因素。Fenwal CS 3000 Plus的采集效率与外周血单核细胞量呈负相 关。Fenwal CS 3000 Plus对红细胞的收集量显著高于Cobe Spectra,并且采集后供者外周血血小板降低程度较Cobe Spectra更严重。结论:Cobe Spectra(Version 6.1)和Fenwal CS 3000 Plus在CD34+细胞的采集能力上无显著差别。 当外周血单核细胞数量高,或是血型不合移植的及血小板减少的供者,推荐使用Cobe Spectra血细胞分离机。

羽流UV-VIS辐射在液体火箭发动机故障诊断中的应用技术研究

为发展基于羽流 UV - VIS辐射光谱的液体火箭发动机故障诊断技术 ,以光谱采集系统为测量手段 ,对三组元模型发动机排气羽流及用以模拟煤油 -氧发动机燃烧的气氧 -煤油火焰的近紫外与可见光谱辐射进行了实验研究 ,利用辐射传递模型对实验结果进行了理论计算 ,利用演化算法对实验结果进行了反算。

樟脑磺酸掺杂聚苯胺在不同有机溶剂中的UV-Vis光谱

由于不同的有机溶剂与樟脑磺酸掺杂的聚苯胺 (PANI.HCSA)有不同的作用 ,故 PANI.HCSA在不同的有机溶剂中有不同的紫外 -可见光谱。本文研究了 PANI.HCSA在有机溶剂间甲酚 (m- cresol)、二甲基亚砜 (DMSO)、N,N-二甲酰胺 (DMF)、N-甲基 - 2 -吡咯烷酮 (NMP)中的 UV- Vis光谱的不同及其变化 。