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21.
Density functional method (DFT) (B3p86) of Gaussian98 has been used to optimize the structure of the Tc_2 molecule. The result shows that the ground state for Tc_2 molecule is an 11-multiple state and its electronic configuration is {}^{11}Σ_g^-, which shows the spin polarization effect of Tc_2 molecule of a transition metal element for the first time. Meanwhile, we have not found any spin pollution because the wavefunction of the ground state does not mingle with wavefunctions of higher energy states. So, that the ground state for Tc_2 molecule is an 11-multiple state is indicative of the spin polarization effect of Tc_2 molecule of a transition metal element: that is, there exist 10 parallel spin electrons. The non-conjugated electron is greatest in number. These electrons occupy different spacious tracks, so that the energy of Tc_2 molecule is minimized. It can be concluded that the effect of parallel spin of the Tc_2 molecule is larger than the effect of the conjugated molecule, which is obviously related to the effect of electron d delocalization. In addition, the Murrell--Sorbie potential functions with the parameters for the ground state {}^{11}Σ_g^- and other states of Tc_2 molecule are derived. Dissociation energy D_e for the ground state of T_{c2} molecule is 2.266eV, equilibrium bond length R_e is 0.2841nm, vibration frequency ω_e is 178.52cm^{-1}. Its force constants f_2, f_3, and f_4 are 0.9200aJ·nm^{-2}, --3.5700aJ·nm^{-3}, 11.2748aJ·nm^{-4} respectively. The other spectroscopic data for the ground state of Tc_2 molecule ω_eχ_e, B_e, α_e are 0.5523cm^{-1}, 0.0426cm^{-1}, 1.6331×10^{-4}cm^{-1} respectively. 相似文献
22.
《Journal of solid state chemistry》2004,177(7):2366-2372
Proton exchange reactions have been performed on tetragonal tungsten bronze-like NaNbWO6 by using nitric acid as an exchanging agent. The characterization of the exchange reaction products has been made by means of chemical analysis, X-ray diffraction, thermal analysis, and IR spectroscopy. The exchange reaction takes place topotactically and the following formula is proposed for the obtained phase of variable composition: Na1−xHxNbWO6·yH2O (0<x?0.46 and 0?y?0.12). Impedance spectroscopy on the present proton exchanged samples indicated that these samples behaved as solid electrolytes under high humidity. As an example, the compound with the composition Na0.68H0.32NbWO6·0.1 H2O exhibits ionic conductivity of 8×10−3 and 1×10−2 S cm−1 at 70°C and 90°C, respectively. 相似文献
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Mattias Edn Jekabs Grins Zhijian Shen Zheng Weng 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2004,169(2):1
Using enhancement of the 27Al central-transition magnetization by applying RAPT prior to 27Al → 29Si cross-polarization, we demonstrate fast acquisition of 29Si one-dimensional MAS and two-dimensional 27Al–29Si HETCOR spectra on a new sialon phase Ba2Al3Si9N13O5. 相似文献
25.
Peixiang Xing Gilles P. Robertson Michael D. Guiver Serguei D. Mikhailenko Serge Kaliaguine 《Journal of polymer science. Part A, Polymer chemistry》2004,42(12):2866-2876
A series of sulfonated poly(aryl ether ketone)s (SPAEKs) were prepared by aromatic nucleophilic polycondensation of 2,6‐dihydroxynaphthalene with 5,5′‐carbonyl‐bis(2‐fluorobenzenesulfonate) and 4,4′‐difluorobenzophenone. The structure and degree of sulfonation (DS) of the SPAEKs were characterized using 1H NMR spectroscopy. The experimentally observed DS values were close to the expected values derived from the starting material ratios. The thermal stabilities of the SPAEKs were characterized by thermogravimetric analysis, which showed that in acid and sodium salt forms they were thermally stable in air up to about 240 and 380 °C, respectively. Transparent membranes cast from the directly polymerized SPAEKs exhibited good mechanical properties in both dry and hydrated states. The dependence of water uptake and of membrane swelling on the DS at different temperatures was studied. SPAEK membranes with a DS from 0.72 to 1.60 maintained adequate mechanical properties after immersion in water at 80 °C for 24 h. The proton conductivity of SPAEK membranes with different degrees of sulfonation was measured as a function of temperature. The proton conductivity of the SPAEK films increased with increased DS, and the highest room temperature conductivity (4.2 × 10?2 S/cm) was recorded for a SPAEK membrane with a DS of 1.60, which further increased to 1.1 × 10?1 S/cm at 80 °C. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2866–2876, 2004 相似文献
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Hiromichi Kurosu Mizuyo Kikuchi Isao Ando 《Journal of Polymer Science.Polymer Physics》1995,33(5):769-775
The solid-state 15N CP/MAS NMR spectra and 15N spin-lattice relaxation times (T1) of doped and dedoped 15N-labeled polypyrroles prepared by electrochemical polymerization, have been measured by means of high-resolution solid-state 15N NMR. The 15N signal of polypyrrole consists of four peaks decomposed by line shape analysis. The four peaks obtained have been assigned to the various structures of polypyrrole. Further, the half-width of the 15N NMR spectra of polypyrroles is discussed as related to the electrical conductivity. © 1995 John Wiley & Sons, Inc. 相似文献
29.
I. A. Anoshko V. S. Ermachenko L. E. Sandrigailo 《Journal of Applied Spectroscopy》2007,74(1):102-106
We present the results of a spectroscopic study of a nonequilibrium plasma in a Hall accelerator, in particular for such an
important parameter as the electron temperature. For the studied conditions, we used the semicoronal equilibrium model, which
relates the intensity ratios for two successive ionization steps for the same element.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 1, pp. 93–96, January–February, 2007. 相似文献
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