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111.
Milind V. Kulkarni Annamraju Kasi Viswanath R. Marimuthu Tanay Seth 《Journal of polymer science. Part A, Polymer chemistry》2004,42(8):2043-2049
Spectroscopic [UV–visible and Fourier transform IR (FTIR)] and thermal properties of chemically synthesized polyanilines are found to be affected by varying the protonation media (acetic, citric, oxalic, and tartaric acid). The optical spectra show the presence of a greater fraction of fully oxidized insulating pernigraniline phase in polyaniline doped with acetic acid. In contrast, the selectivity in the formation of the conducting phase is higher in oxalic acid as a protonic acid media. The FTIR spectra of these polymers reveal a higher ratio of the relative intensities of the quinoid to benzenoid ring modes in acetic acid doped polyaniline. Scanning electron micrographs revealed a sponge‐like structure derived from the aggregation of the small granules in acetic acid and oxalic acid doped polyaniline. A three‐step decomposition pattern is observed in all the polymers, regardless of the protonic acid used for the doping. The second step loss related to the loss of dopant is found to be higher in the oxalic acid doped polymer. In accordance with these results the conductivity is also found to be higher in oxalic acid doped material. The temperature dependent conductivity measurements show the thermal activated behavior in all the polymers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2043–2049, 2004 相似文献
112.
Eduardo Rissi Roberto Rivelino Sylvio Canuto 《International journal of quantum chemistry》2003,91(4):575-585
Density functional theory (DFT), using the most common functionals, and ab initio quantum chemistry methods are used to calculate the rotational constants and dipole moments of the astrophysically important molecules HCN, CH3CN, CH3CNH+, HCCCN, and HCCNC. As far as millimeter‐wave spectroscopy is of interest the DFT methods performed well with most functionals, giving results within ±1% of experiments for rotational constants and ±3% for dipole moments. Analyzing the results obtained with all theoretical models, it may be concluded that the Becke's three‐parameter exchange functional and the gradient‐corrected functional of Lee, Yang, and Paar (B3LYP) and Becke's three‐parameter functional with Perdew–Wang correlational functional [B3PW91/6‐31G(d, p)] give the best performances. A detailed analysis of the electron correlation effects shows that HCCCN is more stable than is HCCNC, by 1.16 eV, with important contribution arising from triple excitations. This result is also compared with those obtained with DFT methods. Despite occasional difficulties, DFT with the currently available functionals are of great utility in quickly assessing spectroscopic parameters of astrophysical interest. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2003 相似文献
113.
The potential of the internal rotation of the methyl group was determined for o-, m-, and p-fluorotoluene cations by pulsed field ionization spectroscopy. The potential of the internal rotational motion was also surveyed for other toluene derivative cations. It was found that the barrier height generally increases by ionization. The increase in the barrier height has been discussed in connection with the reduction of the internal rotational constant B by ionization. The geometrical distortion of the methyl group during the internal rotation has been suggested. 相似文献
114.
The detailed characterization of multifunctional hybrid organosilazane/organosilylamine telechelic oligomers by IR and 1H, 13C and 29Si NMR spectroscopy in one and two dimenions has been undertaken. The specific multifunctional oligomers, comprising NH/NH2 or SiCl functionalities depending on the monomer feed-ratio, were prepared from mono- and di-functionally reacted dichlorodimethylsilane (DDS) and mono-, di-, tri- and tetra-functionally reacted ethylenediamine (EDA). Varying the feed-ratio afforded control of the microstructures of the oligomers and the preparation of oligomers with, in some cases, conterminously located silicon–chlorine (SiCl) groups. The combination of the NMR methods with the IR technique has enabled the detailed microstructural characterization of the oligomers and the identification of the functionalities therein. This approach and the knowledge gained from the DDS/EDA system has been applied to the microstructural characterization of other hybrid organosilazane/silylamine preceramic telechelic oligomers. 相似文献
115.
对水热处理后得到的USY沸石作进一步的酸处理以及采用改进的氟硅酸盐溶液骨架富硅工艺,分别得到了经XPS剖面分析证实为铝分布均匀的超稳Y沸石HAY-Ⅰ和HAY-Ⅱ。IR分析表明,在酸处理过程中从USY沸石中去掉的那部分非骨架铝类与3690cm~(-1)处羟基有关,仍残留在HAY-Ⅰ沸石中的那部分非骨架铝类与3670cm~(-1)和3600cm~(-1)处羟基有关。XRD和化学分析表明HAY-Ⅰ沸石仍含有约50%的非骨架铝类,而HAY-Ⅱ沸石则基本上不含非骨架铝类,HAY-Ⅱ沸石还显示更高的结晶保留度。DTA分析表明,HAY-Ⅰ和HAY-Ⅱ两种沸石的热稳定性均高于USY沸石。 相似文献
116.
117.
Thin films of polystyrene (PS), poly(methyl methacrylate) (PMMA) and polystyrene-polyacrylonitrile copolymer (PS-AN), containing various embedded transition-metal complexes, have been studied by FTIR microscopy. The spatial distributions of the transition-metal carbonyl complexes throughout the thin organic polymer films have been determined by a two-dimensional IR mapping procedure. The spectral variations observed in the distribution of the metal carbonyls throughout the different polymer films are discussed. The IR data show that the technique used to prepare the organometallic-embedded thin films (viz. freeze-drying of solutions followed by hot mechanical pressing of the residues) does in general lead to homogeneous films which may eventually find industrial application, e.g. as membrane sensors for small molecules. 相似文献
118.
A. E. Chmel’ 《Journal of Applied Spectroscopy》1997,64(4):566-568
Using Raman spectroscopy, a quantitative analysis of the distribution of OH− ions on the boundary between a bearing pipe and a glass layer deposited from chlorides in billets for quartz fiber light
guides is carried out. Water penetrated into the light-reflecting shell to a depth of several tenths of a millimeter, depending
on the composition of the doping layer (i.e., ultimately on the temperature of the depsoition process).
A. F. Ioffe Physical-Technical Institute, Academy of Sciences of Russia, 26, Politekhnicheskaya St., St. Petersburg, 194021,
Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 4, pp. 548–550, July–August, 1997. 相似文献
119.
Optical heterodyne magnetic rotation enhanced velocity modulation spectroscopy was employed to observe the visible absorption spectra of the B^2Σ^+_u-X^2Σ^+_g electronic transition of C^-_2. Four hot bands (0,1), (1,2), (2,3) and (3,4) have been observed and the band (3,4) is measured directly for the first time, so far as we know, by absorption. A rotational analysis was carried out to obtain molecular constants. With the Franck-Condon principle and the vibrational Boltzmann distribution, we have estimated the vibrational temperature of C^-_2 to be about 3000K. 相似文献
120.
Al2O3 incorporated HfO2 films grown by atomic layer deposition (ALD) were investigated by high-resolution X-ray photoelectron spectroscopy (HRXPS). The core level energy state of a 15 Å thick film showed a shift to higher binding energy, as the result of a silicate formation and Al2O3 incorporation. The incorporation of Al2O3 into the HfO2 film had no effect on silicate formation at the interface between the film and Si, while the ionic bonding characteristics and hybridization effects were enhanced compared to a pure HfO2 film. The dissociation of the film in an ultrahigh vacuum (UHV) is effectively suppressed compared to a pure HfO2 film, indicating an enhanced thermal stability of Hf-Al-O. Any dissociated Al2O3 on the film surface was completely removed into the vacuum by vacuum annealing treatment over 850 °C, while HfO2 contributed to Hf silicide formation on the film surface. 相似文献