A study of the interaction between perylene and the TiO2(1 1 0)-(1 × 1) surface-based on XPS, UPS and NEXAFS measurements

The interaction between a semi-large aromatic hydrocarbon compound (perylene) and the TiO₂(1 1 0)-(1 × 1) surface under ultra high vacuum conditions has been probed by X-ray photoemission spectroscopy (XPS), ultraviolet photoemission spectroscopy (UPS) and near-edge X-ray absorption fine structure (NEXAFS) methods. UPS measurements of the adsorbate system have been compared with an experimental UPS spectrum of perylene in the gas phase and a calculated spectrum obtained by means of density functional theory (DFT) methods. NEXAFS results of perylene molecules adsorbed on TiO₂(1 1 0)-(1 × 1) were compared with data from an α-phase perylene single crystal. A novel analysis of the valence data has been employed to show that no strong chemical interaction takes place between perylene and the TiO₂(1 1 0)-(1 × 1) surface. Furthermore, angle-dependent NEXAFS measurements and the growth curve results suggest that the perylene molecules are oriented flat down onto the TiO₂ substrate due to weak van der Waals interactions.     

极化子效应对ZnS/CdSe核壳量子点光吸收系数的影响

在有效质量近似下,利用量子力学密度矩阵理论,从理论上研究了考虑极化子效应后核壳量子点中线性、三阶非线性以及总的光吸收系数在不同条件下随入射光能量变化的关系。通过数值计算,分析了电子-LO声子和电子-IO声子相互作用对ZnS/CdSe柱型核壳结构量子点光吸收系数的影响。结果表明,极化子效应对光吸收系数有很大影响,不同声子模式对光吸收系数影响大小不同。考虑电子-LO声子后,光吸收系数被大大提高。另外,入射光强和弛豫时间对系统的吸收系数也有很大影响。     

反演波段对DOAS测量大气中O3的性能影响研究

臭氧(O3)浓度通常被认为是一个地方污染水平的基准,所以其绝对值的准确性至关藿要.在差分光学吸收光谱技术(DOAS)对O3的测量过程中,光谱反演波段的选择可直接决定O3浓度的测量准确度.文章主要研究了在不同光谱波段O3特征吸收结构和差分光学厚度(D')的不同,在不同光谱波段O3浓度反演的干扰来源以及影响程度,确定了实际检测时大气消光对不同波段光强的影响,最后通过对多种污染物标准气体进行了同时临测,计算出标准气体在不同光谱分辨率不同O3浓度时的测量误差,确定了对O3的最适用光谱波段范围.在此波段既能够实现对痕量气体的准确定性定量,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.     

Determination of Organic Chlorine by Aluminium Monochloride Molecular Absorption Spectrometry Using Lead Atomic Line

The present study was conducted to investigate the molecular absorption by AlCl in a carbon rod furnace for determination of chlorine in organic compounds, by using the lead atomic line at 261.418 nm emitted from a Pb-hollow cathode lamp. A deuterium lamp was used for the simultaneous background correction. The method enables rapid and accurate determination of trace chlorine in varying organic samples with good precision. The method was tested on different organic chloro-coumpounds and α-pinene products.     

Spectroscopic Properties and Electronic Structure of (L-Glutamato)(2, 2′-Bipyridine) copper(II)

Cu(L-glu)(bpy)(L-glu = L-glutamato; bpy = 2, 2′-bipyridine) was prepared. Its electronic absorption spectrum and photoacoustic spectrum were recorded at room temperature. They were compared with each other and compared quantitatively with ligand field theory(LFT) and the radical wave function of non-free ions^[1–3]. Therefore, the electronic structure was also investigated with its spectrum behaviors and PLFT^[1–3].     

Optical investigations of conducting polypyrrole under pressure

Abstract

The changes in the characteristics of vibrational and optical properties of the conducting form of polypyrrole under pressure is studied.     

Absorption of shocked benzene

Abstract

We used absorption spectroscopy to observe decomposition of benzene (C₆H₆) subjected to the passage of strong shock waves generated by projectile impact. These measurements were made using a recently developed double-beam, double-pass, fiber-optic-coupled apparatus. Near 13 GPa, we observe absorption throughout most of the visible region, with strong absorption occurring for wavelengths below 400 nm. The absorption is most likely due to a combination of molecular absorption and Mie scattering from carbon particles formed as a result of shock decomposition.     

SPECTROSCOPIC PROPERTIES AND ELECTRONIC STRUCTURE OF [CuCl(L-PROLINATO)(H2O)]

ABSTRACT

[CuCl(L-Prolinato)(H₂O)] was prepared. Its electronic absorption spectrum and photoacoustic spectrum were recorded at the room temperature. A semi-empirical method of ligand-field-theory PLFT was utilized to calculate the d-d transition energy. According to the results, the spectrum was explained satisfactorily.     

Analytical formulas for calculating photoelectric attenuation coefficients

Photoelectric absorption is an interaction in which an incoming gamma ray virtually transfers all of its energy to an atomic electron, usually the most tightly bound K-shell electron of an atom. This paper uses the Win XCOM computer code as a reference base. We found analytical photoelectric attenuation coefficients for researchers using the Monte Carlo simulation program for Z∈ [1; 100] and E∈[10 keV; 3 MeV]. We define a photoelectric effect operator and coefficient operators and a series for photoelectric absorption. We have calculated two polynomial coefficient operators for use with XCOM for photoelectric absorption. We determined 14 energies and atomic number limits for elements, and we find that they are accurate limits of photoelectric absorption for fitting with XCOM.     

Characterization of Phyllanthus amarus herb by inductively coupled plasma mass spectrometric (ICP-MS) analysis,optical absorption and electron paramagnetic resonance (EPR) spectroscopic methods

A powdered sample of Phyllanthus amarus herb of Kadapa district of Andhra Pradesh, India, is used in the present study. ICP-MS analysis indicates that copper is present in higher concentration when compared to other elements. Although the Pb is toxic, it is within the permissible limit. The evaluated soil and herb physico-chemical parameters indicate that the sample is acidic in nature in comparison with the soil. An EPR study on powdered sample confirms the presence of Fe(III), Mn(II) and Cu(II). Optical absorption spectrum indicates that Fe(III) impurity is present in octahedral structure whereas Cu(II) is present in rhombically distorted octahedral environment. MIR results are due to carbonate fundamentals.