Surface Acidity of H-Birnessite: Infrared Spectroscopic Study of Formic Acid Decomposition

This paper presents the adsorption and thermal decomposition mechanism of formic acid on an H-birnessite sample. Changes in the surface and structure were characterized using infrared spectroscopy, N₂ gas adsorption–desorption, and thermal analysis techniques. The acid sites of H-birnessite were investigated by infrared and thermal analysis using pyridine as a molecular probe. Decomposition of formic acid started on H-birnessite at 120°C and was complete at 400°C. Infrared spectra revealed that the molecularly adsorbed formic acid species were transformed to a formate species, and the formate species were transformed to CO. The most stable adsorption structure for formic acid was found as a molecular monodentate configuration.     

Infrared investigation of benzene to 30 GPa transformation to a polymer

Abstract

After a pressure cycle to 30 GPa, benzene transforms to a white solid which can be recovered at ambient. Results obtained from infrared spectroscopy and other physico-chemical methods show that the recovered solid is a highly cross-linked polymer. The molecular structure of benzene is very likely completely altered by the transformation.     

Fourier Transform Infrared Spectroscopic Study of Pesticide Microcapsules Influenced by Formaldehyde to Urea Ratio

Urea–formaldehyde resin is widely used as shell materials for microencapsulation of pesticide by in situ polymerization. A series of acetochlor microcapsules were prepared with different formaldehyde to urea molar ratios in this research. Fourier transform infrared spectroscopic analysis suggests that there hardly exists any chemical interactions between shell materials and the acetochlor core materials, and the structure of urea–formaldehyde pre-polymers and shell materials are significantly different when the ratios of formaldehyde to urea increases. The pre-polymer becomes more hydroxymethylated with higher molar ratios, and hydrogen bonds in shell materials interact stronger as well, thus the ratios of formaldehyde to urea affect encapsulation efficiency by hydrogen bonding interactions, which determines the cross-link degree of the shell materials of the prepared microcapsules.     

Surface tension,shear viscosity and isothermal compressibility of liquid C60 along the liquid-vapour coexistence

The correlations between the surface tension, shear viscosity, and isothermal compressibility, are investigated for liquid C₆₀ at extended regions of temperature and pressure. An improved equation of state [EOS] is employed, based on hard-core plus three Yukawa potential [HC3YK] which facilitates the analytically accurate series mean spherical approximation [SMSA] formalism for the free energy. The present equation of state is utilized to obtain analytical expressions for the thermodynamic functions of interest and discuss the validity of their mutual relations along the spinodal curve of C₆₀.     

Au电极连接富勒烯C32分子的电子结构与传输特性

采用基于密度泛函理论(DFT)和非平衡格林函数(NEGF)的第一性原理方法对富勒烯C₃₂分子及在C₃₂分子的距离最远的两个碳原子处连接Au(1,1,1)电极的分子器件进行了电子结构和电子输运性质的研究.考虑到中间分子与Au电极间距离变化的情况,通过计算得出了在不同距离下分子器件的电子传输谱和I-V特性,分析了各器件的电子结构和电子输运特性产生的原因,并分析了电极与中间分子的连接距离及门电压对分子器件电子输运的影响.得出了电极与所连接的中间分子之     

块菌的傅里叶变换红外光谱研究

块菌是珍稀野生食用菌,其蛋白质和糖类含量较高,块菌多糖具有潜在的药用价值。文章利用傅里叶变换红外光谱技术(FTIR)对五种云南野生块菌作了研究。结果表明,块菌属真菌有其独特的光谱特征,全谱最强峰为出现在1 042和1 077 cm-1附近的强双峰。在脂分子的羰基峰1 742 cm-1及糖类异构体的指纹区1 200～750 cm-1,不同种类、不同产地块菌的光谱有明显差异,另外,正常块菌和霉变块菌的光谱亦有明显差异,主要体现在谱峰吸收强度的变化上,部分谱峰吸收强度比的变化表明,块菌样品变质前后,其蛋白质和糖类物质的含量发生了变化。FTIR光谱提供了块菌成分的有关化学信息,为鉴别块菌和区分块菌的种类、质量提供了简便快捷的手段。     

The Raman and Infrared Spectra and Structures of Ethyl Chloride,Bromide and Iodide

The Raman, infrared and proton NMR spectra of the liquid molecules, C₂H₅-X(X[dbnd]Cl, Br, I) have been recorded. And the molecular structures have been studied on the basis of these spectra. Consequently a non-rigid structure in which a CH₂ group rotates freely with respect to the three hydrogen atoms of CH₃ group is established.     

Studies of Atmospherically Relevant Reactions Using Differentially Pumped Mass Spectrometer and Fourier Transform Infrared Spectroscopy

This article describes recent studies of atmospherically relevant reactions using spectroscopic techniques by our group at the Wadsworth Center. Heterogeneous reactions of SO₂ with either HOBr or HOCl on ice have been studied using a coated-wall flow reactor coupled with differentially pumped quadrupole mass spectrometer, and the reaction of NO₂+HI has been investigated using Fourier transform infrared spectroscopy (FTIR). Reaction probabilities or rate constants have been determined at relevant atmospheric temperatures. Specular reflection-absorption infrared spectroscopy and the temperature programmed desorption technique were employed to study the adsorption of oxalic acid on a Cu surface at 175 K. Reflection-absorption infrared spectroscopy showed that oxalic acid is molecularly adsorbed on the Cu surface. The results obtained from these studies provide a better understanding of atmospheric reactions at a molecular level and enable an assessment of the relative importance of the reactions in the atmosphere.     

355nm激光曝光SU-8胶的XPS谱和FT-IR谱研究

SU-8光胶因具有良好的光刻性能,并可获得稳定的高深宽比而在微加工领域得到了广泛的应用。众多研究采用不同的光源对其进行了多种光刻研究,本文应用355nm激光对SU-8胶进行曝光,分别采用XPS谱和FT-IR谱分析了SU-8胶与激光相互作用过程中,355nm激光对SU-8胶的作用以及反应前后主要成分含量、分子结构的变化,初步探讨了SU-8胶中激光曝光能量与透入深度的关系。     

Group Classification of Biological Tissues by Infrared Spectroscopy

Infrared spectra of rat tissues, RNA tumor virus (Rauschler) and pure RNA and DNA are examined by the technique of frustrated multiple internal reflection (FMIR). An attempt has been made to characterize biologically important tissue components on the basis of infrared spectral analysis and published literature on the subject.

Under the conditions described, rat tissues may be grouped according to their infrared spectra. The spectral differences in vivo between normal and N-nitroso-dimethylamine (DMN)-injected rat liver have been presented to show the usefulness of the FMIR technique for rapid detection of induced changes in the tissue composition.     

Comparative Fourier Transform Infrared Investigation of Oltu-Stone (Natural Carbon Black) and Jet

Fourier transform infrared (FT-IR) investigation of Oltu-stone (natural carbon black) and jet revealed several differences between these carbonaceous materials. The band peaking at about 1000 cm^?1 is the first important difference: while the band in the jet spectra appears as one sharp peak at about 1001 cm^?1, the similar band in the Oltu-stone spectra is shifted to about 1026 cm^?1 with a broad shoulder toward high frequency. Even though the assignment of the shifted band is at present controversial, it may be attributed to carbon-oxygen stretching mode. Second, the doublet bands at about 2912 and 2843 cm^?1 are much more intense in the jet spectra then in the Oltu-stone spectra. They are confidently attributed to aliphatic C-H stretching mode. Finally, the broad water band on setting at about 3750 cm^?1 is maturated in Oltu-stone, and it is much more evident than in that of jet.

Therefore, FT-IR appears as a favorable identification method for these kinds of carbonaceous materials.     

Fourier transform spectroscopy of the CO-stretching band of O-18 methanol

The high-resolution Fourier transform spectrum of the ν₈ CO-stretching band of CH₃¹⁸OH between 900 and 1100 cm⁻¹ has been recorded at the Canadian Light Source (CLS) synchrotron facility in Saskatoon, and the majority of the torsion-rotation structure has been analyzed. For the ν_t = 0 torsional ground state, subbands have been identified for K values from 0 to 11 for A and E torsional symmetries up to J values typically well over 30. For ν_t = 1, A and E subbands have been assigned up to K = 7, and several ν_t = 2 subbands have also been identified. Upper-state term values determined from the assigned transitions using the Ritz program have been fitted to J(J + 1) power-series expansions to obtain substate origins and sets of state-specific parameters giving a compact representation of the substate J-dependence. The ν_t = 0 subband origins have been fitted to effective molecular constants for the excited CO-stretching state and a torsional barrier of 377.49(32) cm⁻¹ is found, representing a 0.89% increase over the ground-state value. The vibrational energy for the CO-stretch state was found to be 1007.49(7) cm⁻¹. A number of subband-wide and J-localized perturbations have been seen in the spectrum, arising both from anharmonic and Coriolis interactions, and several of the interacting states have been identified.     

油菜根肿病的傅里叶变换红外光谱研究

用傅里叶变换红外光谱仪测试了成株期油菜正常植株和根肿病植株的花瓣、叶片、主根、须根四个部位的光谱。光谱显示:两种植株花瓣和叶片中的主要成分是蛋白质、多糖类和油脂类物质;正常植株主根中的主要成分是纤维素和木质素;根肿病植株主根中的主要成分是纤维素、木质素和蛋白质类物质;两种植株须根中的主要成分是木质素和纤维素。对正常和病变植株相同部位的光谱在3600～2800cm-1、1800～1200cm-1和1200～700cm-1三个范围进行了相关分析,花瓣间、叶片间的相关系数在0.971以上,相关度较高;然而主根间、须根间的相关度较低,主根在1800～1200cm-1光谱范围的相关系数只有0.688,须根在1200～700cm-1光谱范围的相关系数只有0.618。结果表明,FTIR可以区分根肿病对油菜不同部位的影响,有望为油菜根肿病的研究提供光谱信息。     

纳米Mn2O3的制备及其红外光谱研究

本言语和化学液相均相沉淀法首次制备了纳米Ｍｎ２Ｏ３利用射线衍射，透射电镜和红外光谱分析方法了其微经持征与物理性质的关系，并对结果作了初步的解释。     

毛头鬼伞的红外光谱研究

利用傅里叶变换红外光谱法(FTIR)研究了人工栽培与野生的毛头鬼伞,及其液化前后的菌盖样品。毛头鬼伞的红外光谱主要由蛋白质、多糖的特征吸收峰组成。人工菌与野生菌的光谱差异表现为蛋白质和多糖的特征峰强度比,野生菌的多糖特征吸收峰要比人工菌的吸收峰明显。菌盖液化黑色物与液化前的菌盖光谱相比,多糖特征峰明显减弱,表明菌褶液化现象主要是多糖的变化。红外光谱结果为毛头鬼伞的进一步的开发研究提供了参考信息。     

彝药金沙青叶胆的傅里叶变换红外光谱研究

金沙青叶胆是常用彝药之一,具有独特而显著的药用价值。本文采用傅里叶变换红外光谱方法(FTIR)对金沙青叶胆的根、茎、花不同部位进行了分析研究。研究表明,其根、茎、花的红外光谱有较大的相似性,主要吸收峰位置基本相同,它们共同显示出该药材独特的红外指纹特征,三者所含主要物质成分基本相同,由此说明在彝医临床应用中将该药全草入药具有其合理性,但其根、茎、花的红外光谱的吸收峰位置、个数、强度、峰形又有一些差异,表明其不同部位所含的化学成分及其相对含量存在一定的差异。本文的分析研究为临床应用及开发利用该彝药提供了科学依据。     

新型L-丙氨酸尾式卟啉锌配合物的合成及其傅里叶变换红外光谱研究

合成了一种新型L-丙氢酸尾式卟啉及其锌配合物，测试并研究了它们在4000-400cm^-1范围内的傅里叶变换红外光谱，对主要谱带进行了经验归属，研究发现，在锌配合物的谱带中3316.9cm^-1、965.8cm^-1和728.cm^-1谱带消失，而在1002cm^-1处出现了四苯基卟啉衍生物所特有的卟啉环骨架的强吸收带，这是Zn（Ⅱ）离子与氨基酸尾式卟啉形成配合物的显著特征。卟啉环的结构敏感谱带出现在1470、1442、1350、1002、994和796cm^-1处。     

Characterisation of human hair surfaces by means of static ToF-SIMS: A comparison between Ga and C60 primary ions

This study deals with the secondary ion yield improvement induced by using C₆₀⁺ primary ions instead of Ga⁺ ones to characterize human hair surfaces by ToF-SIMS. For that purpose, a bunch of hair fibres has been analysed with both ion sources. A high improvement is observed for the detection of amino acids with C₆₀⁺ primary ions as compared to Ga⁺ ions. As an example, a yield enhancement factor greater than 3000 is found for the CNO⁻ peak. A similar gain is observed for the positive secondary ions characteristic of the amino acids. Most of the atomic ions, such as Ca⁺, O⁻ and S⁻, constitute minor peaks with C₆₀⁺ ions while they often dominate the spectrum in the case of Ga⁺ ions. However, with the C₆₀⁺ source, a series of inorganic combination peaks with the elements Ca, S and O are observed in the positive spectra (i.e. HCaSO₄⁺), while they are marginal with the Ga⁺ source. For the mass range beyond 100 m/z and in both polarities, the hair fingerprints are similar with both sources. In average, for a comparable number of primary ions per spectrum, the C₆₀⁺ ion source gives intensities between two and three orders of magnitude higher than the Ga⁺ one.     

On the isotope effect of Tc in squaric acid (H2C4O4)

The phase transition mechanism in squaric acid is reviewed from the viewpoint of the pressure dependence of the O—H—O bond length (2R). The two-dimensional pressure effect on T_c is extracted from the hydrostatic pressure behaviour by taking account of the uniaxial stress applied perpendicular to the layer planes. The result shows that if 2R(H₂SQ) is stretched to 2R(D₂SQ) the phase transition temperature 7^H _c of H₂SQ coincides with T^D _c of D₂SQ. This result supports the suggestion that the phase transition mechanism is of the order-disorder type.