Polarized Infrared and Raman Spectra of 2(3H)-Benzoxazolone

Abstract

The infrared spectra of 2(3H)-benzoxazolone have been measured from 4000 to 180 cm^?1. The polarized spectra of single crystals have been also obtained. The Raman spectra of polycrystalline samples and solutions have been recorded and the polarization of many lines has been determined. On the basis of the i.r. dichroism, Raman spectra and correlative arguments most of the fundamental vibrations have been assigned.     

Mechanisms of formation of near-edge fine structure of <Emphasis Type="Italic">K</Emphasis> X-ray absorption spectra of metallic Cu,Ni, Co (HCP and FCC phases), and Cr

The K X-ray absorption near-edge fine structure spectra of metallic Cu, Ni, Co (hexagonal close-packed and face-centered cubic phases), and Cr have been studied. The experimental spectrum of cobalt has been measured in the high-temperature face-centered cubic phase. The calculations have been performed by the full multiple scattering method in the cluster approximation using the semiempirical muffin-tin potential. The spectra have been calculated for clusters containing from 13 to 935 atoms. It has been demonstrated that the spectra cease to depend on the cluster size for clusters containing about 400 atoms. It has been established that the intensity ratio of two peaks located at the fundamental edge of all the spectra under investigation sharply changes with a variation in the atomic potential strength. The mechanisms responsible for the formation of the near-edge structure of the spectra have been revealed using the results of the model calculations. The studies resulted in good agreement of the calculated spectra with the experiment.     

Time-Resolved EPR Spectra of Photoexcited Copper Porphyrin

Photoinduced spin-polarized transient electron paramagnetic resonance (EPR) spectra of copper 5,10,15,20-tetrakis(3-pyridyl)porphyrin (3PyNCu) in the frozen solution have been observed in the X-band. The time evolution and the temperature dependence of the spectra have been studied. The effect of molecular oxygen in the frozen solution on the polarization pattern has also been examined. The magnetic resonance parameters of the ground state of 3PyNCu have been obtained by comparing the experimental continuous-wave and echo-detected EPR spectra with the numerical computations. The magnetic resonance parameters of the excited states and the photoinduced polarizations have been investigated by time-resolved EPR (TREPR) spectroscopy and numerical analysis. The experimental spectra have been considered as a sum of the polarized spectra of the ground and excited states. Our analysis confirmed that the TREPR spectra consisted of two main patterns: the enhanced signal from the ground state and the multiplet contribution belonging to the excited quartet state.     

Comparative analysis of characteristic electron energy loss spectra and inelastic scattering cross-section spectra of Fe

The inelastic electron scattering cross section spectra of Fe have been calculated based on experimental spectra of characteristic reflection electron energy loss as dependences of the product of the inelastic mean free path by the differential inelastic electron scattering cross section on the electron energy loss. It has been shown that the inelastic electron scattering cross-section spectra have certain advantages over the electron energy loss spectra in the analysis of the interaction of electrons with substance. The peaks of energy loss in the spectra of characteristic electron energy loss and inelastic electron scattering cross sections have been determined from the integral and differential spectra. It has been shown that the energy of the bulk plasmon is practically independent of the energy of primary electrons in the characteristic electron energy loss spectra and monotonically increases with increasing energy of primary electrons in the inelastic electron scattering cross-section spectra. The variation in the maximum energy of the inelastic electron scattering cross-section spectra is caused by the redistribution of intensities over the peaks of losses due to various excitations. The inelastic electron scattering cross-section spectra have been analyzed using the decomposition of the spectra into peaks of the energy loss. This method has been used for the quantitative estimation of the contributions from different energy loss processes to the inelastic electron scattering cross-section spectra of Fe and for the determination of the nature of the energy loss peaks.     

Interference of additional modes in spectra of opal-like photonic crystals in the multiple diffraction regime

The mechanisms of formation of Bragg reflectance and transmittance spectra have been investigated for films of three-dimensional opal-like photonic crystals. Attention has been drawn to the fact that the spectra exhibit an additional short-period interference structure of the novel type due to the multiple Bragg diffraction of light. The spectra have been calculated in the framework of the dynamical three-wave diffraction model taking into account strong spatial modulation of the dielectric function. It has been found that short-period oscillations appear in the spectra due to the spatial quantization of additional modes with a low group velocity.     

功能性ZnS纳米荧光探针的合成及其光谱性质研究

报道了功能性ZnS纳米荧光探针的合成与表征 ,同时研究了纳米粒子的荧光衰变寿命 ,考察了该纳米荧光探针的吸收光谱和荧光发射光谱特性。与此同时 ,研究了不同蛋白质和核酸对该纳米荧光探针的吸收光谱和荧光发射光谱的影响 ,实验表明 ,蛋白质的加入使得该纳米荧光探针的吸收和发射光谱强度均增强 ,而核酸的加入则使其吸收和发射光谱强度均减弱。据此 ,可望将该纳米荧光探针应用于生物大分子的分析测定     

Ultraviolet Absorption Spectra of N-Arylhydroxamic Acids

The ultraviolet absorption spectra of 36 new N-arylhydroxamic acids have been recorded in 95% ethanol. The effect of solvent such as cyclohexane, dioxane, and water on the absorption spectra of hydroxamic acids is examined qualitatively. The spectra of a few hydroxamic acids are also determined in 0.1 N HCl and 0.1 N NaOH to examine the absorption characteristics of the molecular and anionic species. The salient feature of these spectra have been briefly discussed.     

Optical properties of one-dimensional subwave plasmonic nanostructures

Nanogratings formed by parallel gold nanowires on a quartz substrate have been fabricated. Their transmission and reflection spectra have been studied experimentally. Numerical simulation of the transmission (reflection) spectra has been performed. The simulated spectra agree well with the experimental ones. A package has been proposed, which combines the experimental techniques of the structure fabrication and theoretical methods for calculating the parameters of optical spectra. This package is a promising tool for designing and fabricating optoelectronic devices such as filters, polarizers, and switches.     

HRTEM and EELS study of Y2O3/MgO thin films

Y2O3 thin films deposited on (001)-MgO substrate have been investigated by high-resolution transmission electron microscopy (HRTEM) and electron energy loss spectroscopy. Digital processing of the HRTEM images reveals the presence of grains with a crystallographic structure different from that of the rest of the film (Ia3). The spectrum imaging technique has been applied in vicinity of the Y2O3/MgO interface to get a better knowledge of the phases nucleated on the substrate surface. Fine structures of the O K-edge have been studied in detail; actually two kinds of spectra have been detected in the yttrium oxide thin film. These spectra have been compared to self-consistent full multiple scattering calculations (SC-FMS). One family of spectra has then been associated to the well-known Ia3 structure. The other family of spectra has been compared to calculations performed for the other known structures (such as hexagonal or monoclinic) of Y2O3 with a little success. We have finally compared these spectra to calculations performed with a particular atomic arrangement (octahedral) of Y and O atoms, which leads to a good match between experimental and calculated spectra. Our results emphasize the benefit of coupling several techniques such as HRTEM, EELS and SC-FMS for the determination of structures at the nanometric scale.     

Crystallographically-based analysis of the NMR spectra of maghemite

All possible iron environments with respect to nearest neighbour vacancies in vacancy-ordered and vacancy-disordered maghemite have been evaluated and used as the foundation for a crystallographically-based analysis of the published NMR spectra of maghemite. The spectral components have been assigned to particular configurations and excellent agreement obtained in comparing predicted spectra with published spectra taken in applied magnetic fields. The broadness of the published NMR lines has been explained by calculations of the magnetic dipole fields at the various iron sites and consideration of the supertransferred hyperfine fields.     

Modulation of optical pulses under electromagnetically induced transparency conditions: transfer of the Rabi oscillations manifestation from the radiofrequency to the optical range

The relative intensities of lines in resonance Raman scattering spectra of isolated skatole and skatole-water complex have been calculated quantum mechanically. The influence of the intermolecular interaction on these spectra has been considered. Particular features of the intensity distribution in the resonance Raman scattering spectra of indole and skatole have been compared.     

Experimental and theoretical investigations of absolute optical oscillator strengths for valence excitations of nitric oxide

The absolute optical oscillator strength density spectra of nitric oxide in the energy region of 5.0－22.0 eV have been measured by a high-resolution fast-electron energy loss spectrometer. With the calculated results obtained by the multiscattering self-consistent-field method and channel characteristics, the strongly overlapped spectra in the energy region of 7.5－9.3 eV have been analysed and the corresponding partially vibrationally resolved optical oscillator strengths have been estimated from the experimental spectra.     

The E.S.R. and electronic absorption spectra of Chichibabin's biradical

The absorption spectra of a number of saturated hydrocarbons in the vacuum ultra-violet region have been examined and compared with their photoelectron and electron-loss spectra. Important conclusions about the quantum defect associated with the excited electrons and the nature of the excited states have been drawn from the relative positions of these spectra. The Rydberg bands of ethane, which were initially thought to originate in the C-C bond, have been shown to be associated with an electron largely localized in the CH₃ group.     

磷酸盐、锗酸盐和碲酸盐玻璃中Ce3+、Tb3+、Er3+、Tm3+离子的发光和敏化作用的研究——Ⅰ.吸收光谱、荧光光谱和激发光谱

研究了在不同基质玻璃中Ce3+、Tb3+、Er3+和Tm3+离子的吸收、荧光和激发光谱,对发光强度进行了定量的测定。研究了玻璃基质的紫外吸收对发光的影响,并且讨论了无机玻璃的配位场与上述稀土离子的相互作用。     

Theoretical analysis of the structure of excited electronic states, Raman, and resonance Raman spectra of indole in the isolated state and aqueous solution

The structure of the first excited electronic states of indole has been calculated for the isolated state and aqueous solution. The vibrational spectra of isolated indole have been calculated by the DFT method in the harmonic and anharmonic approximations. The resonance Raman spectra of indole have been calculated quantum mechanically in the Herzberg-Teller approximation. The effect of hydrogen bonds on the structure and vibrational (Raman and resonance Raman) spectra of indole has been analyzed.     

Whispering gallery modes and effect of coating on Raman spectra of single microspheres

Raman spectra and fluorescence of BaTiO₃ and silica microspheres of different sizes have been studied. The observed whispering gallery modes (WGMs) have been assigned using theoretical simulations based on the Lorenz–Mie theory. The WGMs are found to have selective enhancements in the Raman spectra. The variations in the Raman spectra with the radial position of the excitation spot and excitation wavelength have been correlated with the morphology‐dependent internal field distributions of the microspheres. The effect of a thin dye coating on the fluorescence and Raman spectra was studied, and a coating thickness of ∼200 nm was estimated from the theoretical simulation of experimentally observed data based on the Aden and Kerker theory. Copyright © 2011 John Wiley & Sons, Ltd.     

Polarized Infrared and Raman Spectra and Ab-initio Calculations of Benzotriazole

Abstract

The i. r. spectra of benzotriazole have been measured from 4000 to 60 cm^?1: polarized spectra of single crystals have been also obtained. The Raman spectra of polycrystalline samples and solutions have been investigated. The structural parameters and vibrational frequencies have been determined from ab-initio Hartree-Fock gradient calculations using the 6–31G* basis set. A detailed arsignment of most of the observed bands has been proposed on the basis of the i. r. dichroism, Raman polarization data and frequency calculations.

     

Optical properties of a polymer host matrix containing mercuric iodide microcrystals

Microcrystals of mercuric iodide have been grown in a polymer matrix with pores 200 nm in diameter. The absorption and luminescence spectra indicate the formation of microcrystals of two (red and orange) modifications in the host matrix. The temperature dependence of the emission spectra and the evolution of absorption and emission spectra in the course of sample ageing have been studied. The evolution of the spectra is governed by the transition from the orange to red modification and the increase in size of microcrystals.     

Quantum-mechanical calculation of the intensity distributions in spectra of resonance hyper-Raman scattering and two-photon absorption of indole and skatole

We have performed a quantum-mechanical calculation of the relative intensities of lines in the spectra of resonance hyper-Raman scattering and two-photon absorption of isolated indole, indole in an aqueous solution, isolated skatole, and skatole-water complex. The effects of hydrogen bonds and intermolecular interaction on the spectra have been considered. Particular features of the intensity distributions in the spectra of indole and skatole have been compared.     

X-ray photoelectron spectra of N,N-dimethylnitramine and N,N-dimethylnitrosamine and their interpretation in terms of molecular orbital calculations

The core and valence electronic energy levels of N, N-dimethylnitramine and N,N-dimethylnitrosamine have been investigated by X-ray photoelectron spectroscopy (XPS), using a Varian IEE-15 instrument. The spectra have been interpreted using several semi-empirical molecular orbital techniques, including CNDO/2, INDO, and Iterative Extended Hückel. Tentative assignments of the valence band spectra have been made. The shake-up spectra have also been investigated and interpreted on the basis of CNDO/S calculations. An XPS study of UV photolysis gave evidence of selective disruption of the NO bond in dimethylnitramine.