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111.
通过实验阐明了同步荧光光谱与普通荧光光谱之间的关系,在此基础上讨论了溶剂散射光对同步荧光分析的影响以及同步荧光分析的灵敏度。 相似文献
112.
基于荧光激发光谱和发射光谱对波长呈高斯分布的设定,本文推导出固定波长同步荧光光谱峰峰值位置、相对强度和半峰宽度等3个主要光谱参数的理论计算式。所提出的计算式应用于若干荧光物质光谱参数的计算,并和实测值、文献计算值作了对照。结果表明,和文献计算方法相比,本法与所研究物质的实际光谱参数较为接近,可为固定波长同步荧光光谱参数的理论计算提供一有效方法。 相似文献
113.
114.
The absorption spectra of Co(II) chloride complexes, containing variable concentrations of chloride ligand, in a molten mixture of 80 mol% acetamide–20 mol% calcium nitrate tetrahydrate, were studied at 313, 333, 353, and 363 K, in the wavelength range 400-800 nm. The melt contains three possible ligands (CH3CONH2, H2O, and NO3
-) for competition with added chloride ligand. Addition of chloride caused a shift of the absorption maximum of octahedral cobalt(II) nitrate towards lower energies and pronounced changes in the shape of the initial spectrum of cobalt(II) nitrate. The effect of temperature changes on the molar absorption coefficient of the Co(II) species was dependent on the chloride concentration and was attributed to the structural changes occurring in the cobalt(II) species. The STAR and STAR FA programs were applied to identify the complex ionic species and to calculate the stability constants of Co(II) complexes formed in this solvent. The results indicate the highest probability of formation of the following complex species: Co(NO3)4
2-, Co(NO3)2Cl2
2-, and CoCl4
2-. Stability constants of each complex were presented for the equilibria occurring at 313, 333, 353, and 363 K. Distribution of the Co(II) species was also calculated over the ranges of chloride concentration and temperature investigated. 相似文献
115.
Trapping Copper Phthalocyanine in a Silica Sono-Xerogel 总被引:1,自引:0,他引:1
R. Litrán E. Blanco M. Ramírez-del-solar L. Esquivias 《Journal of Sol-Gel Science and Technology》1997,8(1-3):985-990
A copper phthalocyanine (CuPc) has been encapsulated in silica. The trapping effects were studied comparing the UV-Vis absorption
spectra of some CuPc solutions and composites prepared under different conditions. The trapped organic molecules’ stability
was monitored during the gelation and drying processes. Leachability test have been carried out with the aim of checking the
trapping efficiency. Hydrolysis water of pH=2 and a molar ratioR
w
=6 mol acid H2O/mol TMOS leads to a higher CuPc stacking angle homogeneity. The increase of Pc induces a narrower mesopore distribution
and helps the stabilization of the composite. 相似文献
116.
Yu. B. Vysotsky V. S. Bryantsev O. A. Gorban 《Chemistry of Heterocyclic Compounds》2002,38(12):1451-1468
The effects of benzannellation, phenyl substitution at the nitrogen atom, protonation at the carbene carbon, ionization, and the state of the carbene center (2 or 2) on the electronic structure, diamagnetic susceptibility, induced -electron ring currents, the 1H, 13C, and 14N chemical shifts, and the energies of the lowest electronic transitions of imidazol-2-ylidenes and their oxo and thio analogs were examined in the bound version of -electron perturbation theory. The calculated and experimental data are compared. 相似文献
117.
Tohru Nishinaga 《Tetrahedron》2004,60(15):3375-3382
A series of hexadehydro[18]annulenes fused with different numbers of p-benzoquinone, 4-6, were synthesized by stepwise transformation of the p-dimethoxybenzene moiety of the precursor dehydroannulene 3 fused with three 3,6-dimethoxy-4,5-dimethylbenzene units at 1,2-positions into p-benzoquinone using ceric ammonium nitrate. The UV-vis spectra of compounds 4 and 5, which have both electron-donating p-dimethoxybenzene unit(s) and electron-accepting p-benzoquinone unit(s) in the π-systems, showed the maximum absorption bands bathochromically shifted in comparison with 3 having only p-dimethoxybenzene units and 6 having only p-benzoquinone units. However, the solvatochromism expected for 4 and 5 was found to be quite weak possibly because the HOMO and LUMO (B3LYP/6-31G(d)) are not localized but rather delocalized over the whole π-systems. 相似文献
118.
57Fe Mossbauer spectroscopy was used to investigate the evolution of Fe-Zn binary metal oxide sorbent in the process of high-temperature fuel gas desulfurization. The results of phase analyses show that Fe-Zn binary metal oxide sorbent is rapidly reduced in hot fuel gas and decomposed to new phases of highly dispersed microcrystalline elemental iron and zinc oxide, both of which become the active desulfurization constituents. A complementary and synergistic effect between active iron acting as a high sulfur capacity constituent and active zinc oxide acting as a deep refining desulfurization constituent exists in this type of sorbent for hot fuel gas desulfurization. 相似文献
119.
邻二甲苯…Ar, N2, NH3(ND3)范德华复合物的共振双光子电离光谱 总被引:2,自引:0,他引:2
在超声分子束中,使用双光子共振电离光谱技术和飞行时间质谱技术研究了复合物邻二甲苯…Ar.N2,NH3(ND3).通过理论计算及同位素光谱效应.合理地归属了这些复合物的光谱.并由此获得这些复合物分子问各种模式的振动频率. 相似文献
120.
Lattice Vibration Spectra. LXIII. Be(IO3)2 · 4 H2O, a Hydrate with Unusual Bonding and Lattice Dynamics The IR and Raman spectra (4000–50 cm?1) of Be(IO3)2 · 4 H2O and of deuterated specimens are recorded at 90 and 300 K and discussed in terms of the unusual relations of the masses of the atoms involved and the large polarization power of the beryllium ions. Thus, the translatory modes of the Be2+ ions (BeO4 skeleton vibrations), the librations of the H2O molecules, and the internal vibrations of the IO3? ions in the spectral regions of 300–400 and 600–1000 cm?1 couple and coincide producing unusual vH/vD isotopic ratios of partly < 1. The H-bond donor strengths of the water molecules is so much increased (due to the very large ionic potential of Be2+ ions, viz. 49 e nm?1) (synergetic effect) that the H-bonds formed are similar in strength as those in hydrates of hydroxides with the very strong H-bond acceptor group OH? (vOD of matrix isolated HDO molecules 2 074 and 2 244 (H2O I) and 2 206 and 2 349 cm?1 (H2O II)) 相似文献