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不同化学环境对Er^3+离子的配位场能级结构的影响 总被引:1,自引:0,他引:1
首次在C3v点群对称汤中,运用双层点电荷配位场(DSCPCF)模型计算了CS3Y2I9晶体中Er^3 离子的59个配位场能级,与实验得到的能级比较,其均方根偏差为24.89cm^-1,而用点电荷配位场(PCF)模型计算的均方根偏差为29.08cm^-1,这说明双层点电荷配位场模型能更好地符合实验结果。同时,详细地分析CsLu2,Cs3Lu2Br9,Cs3Y2I9晶体中Er^3 离子能级结构的变化,由于Er^3 -X^-键共价性的增强,使Er^3 离子的能级重心发生红移,Cl→Br→I的配位场能级的分裂程序减小。 相似文献
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Na3[Tb(C4H4O5)3]·2NaClO4·6H2O晶体的偏振发光光谱的配?… 总被引:1,自引:0,他引:1
以双层点电荷配位场(DSCPCF)模型和不可约张量算符方法,用自编程序计算了三角对称TbODA晶体的配位场微扰能级,并对其偏振荧光谱进行了理论归属,结果与实验相一致,与经典点电荷配位场(PCF)模型的计算结果相比,DSCPCF模型更符合实际。 相似文献
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采用点群链R(3)*O*D3*关系标记D3*点群的斯塔克能级。基于双层点电荷配位场(DSCPCF)和经典的简单点电荷配位场(PCF)两种模型,利用自编的计算程序对三角对称(D3)的[Er(C4H4O5)3].2NaC lO4.6H2O晶体中Er3+离子的65个配位场微扰能级进行了理论计算和归属,计算结果与实验能级进行比较,DSCPCF模型得到的均方根偏差(σ)为19.9 cm-1,而PCF模型计算的为25.5 cm-1,表明前者模型更为优越,它是基于实际的配位结构并且仅包含较少的拟合参数。 相似文献
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Na3[Tb(C4H4O5)3]·2NaClO4·6H2O晶体的偏振发光光谱的配位场分析 总被引:2,自引:0,他引:2
以双层点电荷配位场(DSCPCF)模型和不可约张量算符方法,用自编程序计算了三角对称TbODA晶体的配位场微扰能级,并对其偏振荧光光谱进行了理论归属,结果与实验相一致.与经典点电荷配位场(PCF)模型的计算结果相比,DSCPCF模型更符合实际. 相似文献
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采用点群链R(3)(∪)O(∪)D3D3关系来标记D3点群的斯塔克能级.基于双层点电荷配位场(DSCPCF)和经典的简单点电荷配位场(PCF)两种模型,利用自编的计算程序,对三角对称(D3)掺杂晶体YAB:Eu中Eu3+离子的配位场微扰能级进行理论计算和归属.通过与实验能级比较,结果表明:按照配合物的实际配位结构,利用较少的拟合参数,PSCPCF模型得到比PCF模型更为合理的能级分布和精确的能级分裂值. 相似文献
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The synthesis of derivatives of 3-amino-3-deoxy-L-erythrose by LAH or LAD reduction of the oxime of 1,2-O-isopropylidene α-L -glycero-tetros-3-ulofuranose is described. 相似文献
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γγγ-Trifluorocarbonyl compounds are easily obtained in a good yield by introduction of the 1,1,1-trifluoroethyl moiety (CF3-CH2-) on the -methylene group of a ketone. 相似文献
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Thin films of methylammonium lead halides, CH3NH3PbI3 and CH3NH3PbI3-xClx, were deposited onto symmetrical microstructured electrode arrays of gold or platinum on Si/SiO2 wafers. Polarization studies were carried out on perovskite films under vacuum in the dark. For poling, a constant voltage was applied to the samples while the temperature was cycled between 295 K and 4 K. The measured current densities depending on the temperature showed distinct characteristics relating strongly to the crystal phase and the dielectric properties of the perovskite films. Voltage sweeps were carried out at different scan rates at specific temperature intervals after poling. The polarization of the films due to the migration of iodide vacancies in direction of the blocking perovskite/metal interface was frozen almost up to room temperature. Charge carriers were only able to cross the blocking barrier and contribute to the current where the ions have accumulated during poling. All J-V curves showed hysteresis: inverted and regular hysteresis at room temperature and below, respectively. Inverted hysteresis originates from the slow accumulation of ions at the blocking barrier, while regular hysteresis arises from a distortion in the adjacent crystals which will be discussed. 相似文献
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Recent computational studies on the addition of ammonia (NH3) to the Al3O3- cluster anion [A. Guevara-Garcia, A. Martinez, and J. V. Ortiz, J. Chem. Phys. 122, 214309 (2005)] have motivated experimental and additional computational studies, reported here. Al3O3- is observed to react with a single NH3 molecule to form the Al3O3NH3- ion in mass spectrometric studies. This is in contrast to similarly performed studies with water, in which the Al3O5H4- product was highly favored. However, the anion PE spectrum of the ammoniated species is very similar to that of Al3O4H2-. The adiabatic electron affinity of Al3O3NH3 is determined to be 2.35(5) eV. Based on comparison between the spectra and calculated electron affinities, it appears that NH3 adds dissociatively to Al3O3-, suggesting that the time for the Al3O3-NH3 complex to either overcome or tunnel through the barrier to proton transfer (which is higher for NH3 than for water) is short relative to the time for collisional cooling in the experiment. 相似文献
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The thermal behaviors of clusters [Ag3WS3Br](PPh3)3 and [Cu3WS3Br](PPh3)3 (PPh3=triphenyl phosphine) in a nitrogen atmosphere were studied under the non-isothermal conditions by simultaneous TG-DTG-DSC and EDS techniques. The results showed that the evolution of PPh3 generally proceeded before the release of the other moiety in one or two step-mode. The mechanisms, the kinetic and the thermodynamic parameters for decomposition of PPh3 of both clusters were determined and calculated by jointly using several methods, which showed that its evolution was controlled by Avrami-Erofeev equation. The results also showed that there was no new stable phase composed of W-Ag(Cu)-S-Br after release of organic moiety PPh3 and that CVD method was not applicable to their further processing. 相似文献