Infrared Spectra of Water in Aqueous Solutions Using Internal Reflection Spectroscopy

Abstract

There has been a continuing interest in the structure of water and of aqueous solutions, and many studies have employed spectroscopic techniques. These have frequently involved absorption spectroscopy in the near-IR range, and Raman scattering. In general, however, the normal IR range has been but little used except for studies of HDO-containing solutions, and the region near 3500 cm^?1 of the intense H₂O absorption has been almost completely avoided. Transmission techniques have been exclusively employed with absorption spectroscopy. Internal reflection spectroscopy (IRS) techniques have been employed to examine aqueous solutions, but the emphasis was placed on studying the solute rather than the solvent. Also, the solute concentrations which had been employed in transmission studies have been rather high. We now suggest the feasibility of carrying out structural studies of aqueous solutions by using IRS techniques to record spectra in the IR range, employing solutions of relatively low concentrations. For example, the lowest concentration of aqueous HCl solution examined by Ackermann¹ was 2.5 M by transmission techniques in the 4000-1100 cm^?1 range; in contrast, using IRS, the perturbations of the O-H stretching and deformation bands of H₂O could be observed with 0.1 M HCl.     

Applicability of Spectroscopic Methods to the Determination of Aluminium in Biological Samples

A comparative investigation was carried out of the suitability of atomic absorption spectrometry and of emission spectrography with hollow cathode and arc excitation sources for determination of aluminium in biological samples. The three methods give reliable results. Hollow cathode emission spectrography was found to be influenced to a lesser extent by matrix effects than the other two techniques. On the other hand atomic absorption spectrometry presents some remarkable advantages insofar rapidity of analysis and detection limits are concerned.     

Infrared Absorption,Nuclear Magnetic Resonance and Electronic Spectra of N-Hydroxyureas and Carbamates

During the course of investigating the anticancer activities of new compounds, we have synthesized a series of novel cyclic N-hydroxyurea derivatives and several carbamate intermediates^1–3. Infrared absorption, nuclear magnetic resonance, and electronic absorption spectra were examined in order to confirm the identities and to study the molecular structure of these compounds.     

A Modified Version of the Grimm's Glow Discharge Lamp for Use as a Demountable Hollow Cathode Emission Source. V. Determination of Minor Constitutents and Trace Elements in Steel

The applicability of the modified hollow cathode emission source to the determination of some elements usually contained in steel was tested in the case of chromium (0.144 – 3.07%), copper (0.090 – 0.49%), manganese (0.016 – 1.42%), molybdenum (0.007 – 1.41%), nickel (0.048 – 5.15%, silicon (0.013 – 0.81%), and vanadium (0.034 – 0.64%). The linearity of the calibration curves was found to be highly satisfactory, the Bravais - Pearson correlation coefficient ranging from 0.97 to 0.99. Moreover, results showed that background intensity is negligible and that blackening values can be plotted without resorting to internal standards or other preliminary corrections.     

Electronic Absorption Spectra of Some Fluoroaminotoluenes

Abstract

The near ultraviolet absorption spectra of 2-fluoro-5-amino-; 3-fluoro-4-amino-, 3-fluoro-6-amino-and 4-fluoro-2-aminotoluene have been investigated in vapour phase. The strongest band appearing at 2887.5 Å (34621 cm^?1), 2966.1 Å (33704 cm^?1), 3026. 7 Å (33029 cm^?1) and 2891.4 Å (34575 cm^?1) in the respective molecules has been identified as the 0,0 band. All the bands have been analysed in terms of some ground and excited state fundamentals. The assignment of the fundamental frequencies to the probable modes of vibration have also been discussed.     

The Electronic Absorption Spectra of Some Polysubstituted Arenetricarbonylchromium Complexes

The absorption spectra of a series of polysubstituted arenetricarbonylchromium complexes were studied. A linear correlation between the extinction coefficient of the longest wavelength band and the sum of the Hammett σ_p+ values was obtained.     

A Modified Version of the Grimm's Glow Discharge Lamp for Use as a Demountable Hollow Cathode Emission Source. II. The Current Intensity-Voltage Characteristic Curves

The dependence of resulting voltage on applied current intensity in a modified commercially available hollow cathode lamp is determined in the case of aluminium, copper and graphite cathodic materials in an extended range of argon carrier gas pressures and for five different cathode - anode distances. Experimental results show that the modified emission source affords high stability discharge in a wide range of experimental parameters.     

Determination of Copper and Aluminium in Steel by Means of Hollow Cathode and Glow Discharge Light Sources: A Comparative Study

Abstract

The applicability of hollow cathode and glow discharge light sources to the determination of minor constituents in steel was tested in the case of copper (0.033 ? 0.34[wt]%) and aluminium (0.015 ? 0. 16%). The linearity of the calibration graphs, reflected by the Bravais-Pearson coefficient, was found to be slightly improved in all the cases investigated when operating with hollow cathode. Furthermore, results showed that blackening values of the analytical lines can be plotted directly without resorting to reference lines.     

Infrared Absorption Spectra of Undoped and Doped Few-Layer Graphenes

The infrared absorption spectra of undoped few-layer graphenes with the layer number of N = 1-6, the hole- and electron-doped few-layer graphenes with the layer number of N =1-4 have been studied based upon the tight-binding model. It is found that in contrast with the featureless optical spectrum of the undoped monolayer graphene, the undoped AB-stacking bi-, tri-, tetra- and more-layer graphene exhibit characteristic jumps in their infrared absorption （IR） spectra, which are caused by coupling between different layers. It is also found that the clear peaks exist in the IR spectra of the hole or electron-doped hi-, tri- and tetra-layer graphenes, which are induced by the strong IR transitions between their parallel valence or conduction bands. Based upon their different IR spectra, a powerful experimental tool has been proposed to identify accurately the layer number and doping type for the few-layer graphenes.     

空心阴极光源在原子发射光谱分析中的应用

本文介绍了空心阴极光源发射光谱分析中用地测定痕量元素的特点,供电电源的种类,阴极灯及电极,载气的选择等。并介绍了空心阴极光源在痕量分析上的应用。     

Substituent and Solvent Effects on The Electronic Absorption Spectra of Phosphapyrimidine Derivatives

U.v spectra study of phosphacgclic compounds with tetracoordinated ring phosphorus atom has been an object of a rather limited number of WOZkS. There are only few works on U.V. absorption spectra of cyclic phosphonitriles which reveal a specifio character of their Π-electronic structure¹; besides, there are some data on a significant low - frequency shifting of the electronic spectrum of 1.1 - diphenylphos-phabemene against that of benzene². This communication presents an analyisis of the experimental findings on electronic absorption spectra of a Wide variety of substituted phospha-pyrimidines, PhP, (1,2,6 - phosphadiazines) for elucidating the nature of the observed absorption ban and for studying electronic distribution as well as separate characteristics of the php moLecules in the ground and excited states.     

正交投影用于红外光谱图中光谱提取及背景扣除

利用正交投影方法以及原始信号及其投影与背景矢量之间的线性关系,确定背景光谱,从而将待测组分的红外光谱从混合物光谱中提取出来,达到扣除背景及分辨重叠光谱之目的。本方法用于二氯乙烷及丙酮中各组分红外光谱的提取,获得了满意的结果。     

Comparative Investigations on the Reproducibility of the Hollow Cathode,Glow Discharge and Spark Light Sources

A comparison between the constancy and reproducibility of the hollow cathode, glow discharge and spark light sources was carried out. Samples of pure copper as well as of commercial brass and steel were investigated. Results show that the hollow cathode produces a better reproducibility of the measurements in all the cases examined.     

Electronic Absorption and Fluorescence Spectra of Fluorescein in Aprotic Solvents

The absorption, excitation and fluorescence spectra of fluorescein in ethyl acetate and acetone were obtained. It was verified that the neutral lactonic form of fluorescein is present in dilute solutions of those organic solvents. However, in concentrated solutions it was observed a shift of the dissociation equilibrium to form the neutral zwitterionic form of the dye in both electronic ground and excited states.     

Electronic Absorption Spectra of Neutral and Charged Silver Molecular Clusters

The structural, energy, and optical properties of charged and neutral molecular clusters (MCs) of silver Ag_n (n = 2–5) have been simulated within the density functional theory (DFT). It has been shown that the electronic absorption spectrum of neutral MCs is shifted toward lower energies compared to the charged ones. The strengths of the oscillators of neutral MCs are mainly larger than the ones of charged MCs. A comparison of the simulation results with the previously obtained experimental ones for glasses with silver MCs has been carried out.     

固相果糖的太赫兹及红外特征吸收谱研究

果糖是一种常见于蜂蜜和多种植物中的简单酮糖,属于三种可食用单糖之一,可与葡萄糖结合形成双糖蔗糖。纯净的果糖常温呈白色晶体状,具有甜度高、升糖指数低等优点,广泛应用于食品行业。截止目前,由于针对固相果糖的太赫兹和红外特征吸收谱研究大多局限于单纯的实验测试或者基于单分子理论计算,缺乏较为系统完善的研究,因此从理论和实验上系统研究了固相果糖的太赫兹特征吸收谱及红外特征吸收谱,首次报道了固相果糖在频谱大于3.0 THz以外的特征吸收峰的实验值,采用基于单分子的MP2和B3LYP泛函以及基于晶胞的PBE和PW91交换相关泛函计算获得了固相果糖太赫兹及红外特征吸收谱,并与实验获得的固相果糖太赫兹及红外特征吸收谱进行了比对分析,发现基于晶胞的PBE和PW91交换相关泛函计算结果与实验获得的果糖太赫兹特征吸收峰更相符,表明固相果糖在0.1～4.0 THz的大多数太赫兹特征吸收峰源自分子间相互作用而非分子内相互作用,揭示了果糖分子周围环境对果糖振动模式的显著影响。     

Electronic Absorption Spectra of Two 3-Aryl-pyridazinium-2,4,6-picryl-benzoyl-methylids

The visible electronic absorption spectra of two carbanion disubstituted cycloimmonium ylids having a 3-aryl-pyridazinium derivative as cation and a common disubstituted carbanion (-2,4,6-picryl-benzoyl) were studied in solvents with different physical and chemical properties. The visible electronic absorption band of 3-aryl-pyridazinium ylids is attributed to an electron charge transfer from the carbanion toward the heterocycle. The solvent effects on the visible electronic band of the studied ylids were described both by empirical parameters defined by Kosower and by using the theory of a dielectric homogeneous solution. Some remarks about the nature of the molecular interactions in the 3-aryl-phthalazinium-2,4,6-picryl-benzoyl methylid solutions are made in this paper on the basis of solvatochromic study.     

高胆固醇血样的红外吸收光谱研究

红外光谱法及与其相关技术的应用研究,促进了光测技术的迅猛发展。文章针对血液的红外光谱分析这一重要课题, 提出了血液的红外吸收光谱分析新技术, 通过在一定的频谱范围内对正常血样与异常血液的红外吸收光谱进行实验测量和分析, 可以判断血样是否异常,其实验和分析方法具有一定的先进性。文章中研究了正常血样和高胆固醇血样的红外吸收光谱之间的差别, 并给出了人的正常血清与高胆固醇血清的红外吸收光谱以及分析结果,研究结果表明它们的吸收率、吸收峰位置以及吸收率之比之间的差别可以作为检验正常血样与异常血样的依据,从而为应用于疾病诊断方面提供了重要的参考。     

硅基锗薄膜的红外吸收谱和电学特性

为了解退火对硅基锗薄膜的质量、红外吸收、透射率和电学性质的影响,采用分子束外延方法用两步法在硅基上生长锗薄膜。将生长后的样品分成两部分,其中一部分进行了退火处理。对退火前后的样品用高分辨X射线双晶衍射仪测量了(400)晶面的X射线双晶衍射摇摆曲线,用傅里叶红外光谱仪测量了红外透射率和吸收谱,并用霍尔效应仪测量了退火前后样品的载流子浓度、迁移率、电阻率、电导率和霍尔系数。结果表明,退火后的薄膜质量明显提高。退火后大部分区域吸收增大,透射率明显减小,615~3 730 cm-1区间的透射率均比退火前降低了20%以上。退火后的体载流子浓度增大到退火前的23.26倍,迁移率增大到退火前的27.82倍。     

α，α‘—二氧代烯酮环二硫代缩酮类化合物的特征红外光谱（Ⅲ）

研究了5种α，α‘-二氧代烯酮环二硫代缩酮类化合物的碳基、碳碳双键、碳硫等一些特征红外光谱，尤其着重研究了共轭体系下的各种特征谱带随化学结构而变化的规律。