Physicochemical Studies on Solid Products of Reactions of Chromyl Chloride and Chromyl Acetate with Alkylaromatics. Part II. Electronic Absorption Spectra

The electronic absorption spectra of some chromium(IV) complexes as the products of chromyl chloride and chromyl acetate reaction with alkylaromatics have been studied in some organic solvents. A detailed computer analysis of the spectra including resolution into component bands as well as calculation of crystal field parameter Dq, Racah's parameter B and Franck-Condon analysis of the vibronically structured charge-transfer O—Cr band have been performed. The solvent effect on the Dq parameter has been established.     

高分辨分子吸收光谱中的波长校准方法

本文提出高分辨分子吸收光谱中,以碘分子谱作为参考标准的波长校准方法,编制了以人机交互方式自动完成波长校准的软件,并应用于16 422-17 896cm^-1可见光波段范围内的N2^ 分子离子的高分辨吸收谱线的波长校准,结果表明其绝对准确度可达0.006cm^-1。     

The Electronic Absorption Spectrum of Hafnium Monochloride

Abstract

Intracavity laser spectroscopy has been applied for investigation of absorption spectrum of HfCl molecule. In the region 560–700 nm 59 bands have been obtained. Rotational structure analysis of 0–0 band indicated that Hund's case (c) of angular moment coupling applied to this molecule. The molecular constants (cm^?1) calculated for upper and ground electronic states are: ω′ = 353.05 cm^?1, ω″ = 379.65 cm^?1, B′=0.21486 cm^?1 B″ = 0.21801 cm^?1.     

A general formula of two-dimensional Franck-Condon integral and the photoelectron spectroscopy of sulfur dioxide

We derived a general formula of Franck-Condon integral for two-dimensional harmonic oscillators () taking into account the Duschinsky effect and applied it to study the photoelectron spectroscopy of SO₂ and . The equilibrium geometries and harmonic vibrational frequencies of , SO₂ and were calculated by using the density functional theory (B3LYP functional) and the coupled cluster singles and doubles with perturbative triples [CCSD(T)] methods with various basis sets up to 6-311+G(3df) and aug-cc-pVTZ. The adiabatic ionization energy and electron affinity were computed by using the CCSD(T) method extrapolated to the complete basis set limit with aug-cc-pVXZ (X = D, T, Q, 5). The simulated photoelectron spectra of both SO₂ and are in accord with the experiment. While the Duschinsky effect plays a role for some weak transitions of SO₂, it can be neglected for . A splitting observed in the experimental photoelectron spectrum of SO₂ is interpreted as contributing from hot bands and combination bands of ν₁ and ν₂, rather than arising from perturbation of a potential barrier as previous researchers proposed. The calculated adiabatic ionization energy and electron affinity are in agreement with the experiment within 0.027 and 0.040 eV, respectively.     

Analysis of the Electronic Vibrational Spectra of Bisanthene by Calculating Normal Modes

At 4.2 K, the quasiline fluorescence and fluorescence-excitation spectra (in the region of the S ₁ S ₀- and S ₂ S ₀ transitions) of bisanthene in n-hexane have been obtained. Using the MO/M8ST method, the calculation of the A _g normal modes in the S ₀, S ₁, and S ₂ electronic states was carried out for the bisanthene molecule; the relative intensities of the transitions in the corresponding vibronic spectra were also calculated. The analysis of the results of calculations and experiment made it possible to draw conclusions on the form of the modes for a number of normal vibrations which are active in the bisanthene vibronic spectra.     

提高大气吸收光谱测量分辨率的新方法

在仪器函数和吸收线型已知的情况下 ,提出了一种非线性拟合退卷积法 ,用于提高气体吸收测量的光谱分辨率。数值模拟和实际应用都表明 :该方法用于室内气体吸收光谱的测量 ,在保持吸收线型不变的情况下 ,可以显著地提高测量的光谱分辨率 ,降低测量噪声。将该方法用于怀特池中模拟大气吸收光谱测量 ,减小了激光线宽对测量结果的影响 ,获得了比较理想的结果。     

Electronic Structure Analysis of USiO4

Uranium is a member of Actinides and plays important role in nuclear science and technology. Electronic and structural investigations of actinide compounds attract major interest in science. The electronic structure and chemical bonding of coffinite USiO4 are investigated by X-ray Absorption Fine Structure spectroscopy （XAFS）. U L3- edge absorption spectrum in USiO4 is compared with U L3-edge spectra in UO2 and UTe due to their different electronic and chemical structures. The study presents XANES （x-ray Absorption Near-Edge Structure） and Extended XAFS （EXAFS） calculations of USiO4 thin films. The full multiple scattering approach has been applied to the calculation of U L3 edge XANES spectra of USiO4, UO2 and UTe, based on different choices of one electron potentials according to Uranium coordinations by using the real space multiple scattering method FEFF 8.2 code.     

Intracavity Electronic Absorption Spectra of MoO and WO Molecules in the Visible Region

Absorption electronic spectra of MoO and WO molecules have been investigated by a intracavity laser technique in the region 550–800 run. New features have been discovered.

As for MoO molecule the rotational analysis of the four bands have been carried out for the first time. Two of these bands were referred to 0–0 transitions arisen from the new (probable triplet) low-lying electronic state, two other bands were referred to transitions arisen from excited components of X⁵II ground state.

As for WO molecule the rotational analysis of 0–0 and 1–0 bands represented A-X and B-X systems have been carried out for the first time. The new band has been discovered which has been referred to new electronic transition.

Molecular constants of new states of both molecules studied have been evaluated.     

The Electronic Absorption Spectra of Binuclear Complexes,[Cu(o-phen) (sal)No3 and [Cu2 (sacch)4(im)4] Crystal

The electronic absorption spectra of crystals of the title componds were recorded and the experimental results were explained quantitatively with the ligand field theory and the radial wave function of bound Cu(II) cation. With these spactra, the range of magnetic interactions between two Cu(II) ions of the title compounds are discussed.     

Solvent Effects on the Electronic Absorption Spectra of Cr(III) Complexes

An influence of the protic solvents on the electronic absorption spectra of chromium (III) complexes was investigated. The high correlation between dielectric constant of solvents and the crystal field parameter Dq as well as between refractive index and oscillator strength of d-d bands were observed. The significance of the ligand - second sphere interactions for studying of solvent effect on complex spectra was stated.     

Polarization of the 274 nm Absorption System of Benzoxazole: A Band Contour Analysis

Abstract

The rotational contour of the origin band of the 274 nm absorption system of benzoxazole vapour has been analyzed and found to be type A. The transition is thus A ¹A (π π ^?) → X ～ ¹A with the transition moment lying close to the long axis of the molecule. Geometrical changes upon excitation are small.     

狭缝中蒸发水分子的红外吸收光谱（英文）

本文研究了硅片狭缝内水分子蒸发过程中的红外光谱吸收特性。通过改变相对于硅片狭缝的红外光偏振方向(水平:偏振方向与硅片狭缝方向平行;垂直:偏振方向与硅片狭缝方向垂直),测量了水分子在3 900～3 600 cm^-1(伸缩振动)和1 800～1 400 cm^-1(弯曲振动)的偏振红外光吸收。结果表明,经硅片间隙蒸发出来的水分子,在3 900～3 600 cm^-1(伸缩振动)和1 800～1 400 cm^-1(弯曲振动)区间,对垂直偏振光吸收较强,对水平偏振光吸收较弱,表明毛细效应导致蒸发的水分子偶极矩方向倾向于硅片狭缝的法线方向。     

Origin Band Shifts Upon Deuteration in the 280 nm Absorption System of Benzimidazole

Abstract

Five deuterated derivatives of benzimidazole have been prepared and their sharp 280 nm vapour phase electronic absorption spectra recorded. When hydrogen atoms bonded to carbon are substituted, the origin band shifts to higher energies by 29 cm^?1 per D atom, a value close to that found in benzene and some monosubstituted benzenes. When the hydrogen bonded to nitrogen is substituted, a much smaller shift is observed.     

差分吸收光谱法测量大气污染的测量误差分析

差分吸收光谱技术被广泛地应用于测量大气中微量元素的浓度,尽管该技术利用最小二乘法来反演待测气体的浓度,能够得到很高的测量精度。但是,由于仪器本身的噪声以及测量波段其它气体的干扰等,使得仪器的测量有一定的误差,而且上述因素还决定着仪器的测量下限。对差分吸收光谱方法的测量误差以及引起误差的原因作了详细的分析。     

Comparative X-Ray Absorption Analysis of the Spectrum of Vacant Electronic States in Cobalt and Nickel Tetraphenylporphyrin Complexes

Physics of the Solid State - The energy distributions and the properties of the lower vacant electronic states in cobalt and nickel tetraphenylporphyrin complexes CoTPP and NiTPP are studied by...     

分辨率对大气中痕量污染气体的DOAS测量性能影响研究

在差分吸收光谱(DOAS)测量过程中,光谱分辨率的选择直接决定了污染气体浓度的测量准确度.主要研究了光谱分辨率对污染气体被榆测到的特征吸收结构形状的影响,以及差分吸收截面随分辨率的变化趋势,从而确定了光谱分辨率对污染气体最低可检测浓度的影响,通过研究分辨率与光强的关系,确定了分辨率与信噪比(S/N)的函数关系式,得出了DOAS测量NO2,O3,和SO2的最佳信噪比范围,对多种污染物标准气体进行了同时监测,计算出标准气体在不同光谱分辨率下的测量误差,确定了对NO2,O3和SO2监测的最适用的分辨率范围.在此分辨率范围既能够实现对痕量气体的准确定性定量测量,又能达到测量所需要的高灵敏度,强选择性和适用的时间分辨率.通过在北京丰台区的实际监测得到了与点式仪器测量结果很好的一致性.     

Electronic and Infrared Spectroscopic Studies of Aggregation of Cholesterol

A number of reasons and causes has been put forward to understand and explain the process of atherosclerosis, or plaque formation in arteries, and the strategies to combat it. We wish to communicate that the increased level of alkalinity in serum plays an important role in atherosclerosis. On one hand, higher alkalinity helps monomer cholesterol to dimerize, supporting plaque formation. On the other hand, this converts polymer (higher aggregates) into dimer (a lower aggregate). The other finding is that the presence of a certain class of molecules in serum, part of whose bonding structure is ‐CH₂‐O‐CH₂‐, for example, dioxane (maybe as a pollutant), promotes dimerization of cholesterol, which may set in motion the process of plaque formation. At the same time, higher aggregates (insoluble) are converted to dimer (relatively more soluble). This finding could be strategically employed to tackle atherosclerosis.     

Franck-Condon transitions and thermodynamics of photoinduced processes of orientational relaxation in polar solutions

Polar luminescence probe+polar medium subsystems are considered. True minimization parameters of the free energy F are obtained. It is shown that Franck-Condon transitions between F-terms of different electronic states are generally not “vertical”. A complete thermodynamic classification of photoinduced processes of orientational relaxation in the excited S₁ and ground S₀ states is presented. Depending on the excitation conditions they can be either exo- or endothermic, spontaneous or induced (not spontaneous), and accompanied by an increase or decrease in entropy. Indifferent processes also take place. Regularities of shifts of fluorescence spectral bands and burned holes in time-resolved experiments are discussed. Institute of Molecular and Atomic Physics, Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 6, pp. 753–765, November–December, 1997.     

Ligand Exchange and Nature of Luminescence Centers in the Crystals of Uranyl Nitrates and Perchlorates

We obtained complexes of uranyl nitrates and uranyl perchlorates with neutral ligands in crystalline and amorphous states and also with variable composition (as regards both water and the quantity of acid ligands entering into the first coordination sphere of UO₂ ²⁺). We studied their luminescence spectra at T = 77 K. Correlation between the frequencies of electronic and vibronic transitions and the donor numbers of neutral ligands has been established. The possible ways of replacing neutral ligands in the first coordination sphere of UO₂ ²⁺ have been analyzed as well as the composition and structure of the complex systems formed in this case.