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91.
《Journal of computational chemistry》2017,38(12):892-900
An accurate potential energy surface of sulfur dioxide, SO2, in its ground electronic state has been determined from ab initio calculations using the coupled‐cluster approach in conjunction with the correlation‐consistent basis sets up to septuple‐zeta quality. The results obtained with the conventional and explicitly correlated coupled‐cluster methods are compared. The role of the core–electron correlation, higher‐order valence–electron correlation, scalar relativistic, and adiabatic effects in determining the structure and dynamics of the SO2 molecule is discussed. The vibration‐rotation energy levels of the 32SO2 and 34SO2 isotopologues were predicted using a variational approach. It was shown that the inclusion of the aforementioned effects was mandatory to attain the “spectroscopic” accuracy. © 2017 Wiley Periodicals, Inc. 相似文献
92.
2003—2007年中国儿童铅中毒率的分析研究——发铅检测结果 总被引:2,自引:1,他引:1
通过计算机检索收集了2003—2007年间公开发表的、关于儿童发铅水平和铅中毒率的中文文献,对涉及8省16万人作了调查分析。结果表明,近5年内中国儿童的平均发铅水平为7.5μg/g,铅中毒率平均为27.5%,与同一时期血铅检测结果一致。 相似文献
93.
A three‐dimensional potential energy surface of the electronic ground state of ZnH2 (${X}^1\sum _g^ +$ ) molecule is constructed from more than 7500 ab initio points calculated at the internally contracted multireference configuration interaction with the Davidson correction (icMRCI+Q) level employing large basis sets. The calculated relative energies of various dissociation reactions are in good agreement with the previous theoretical/experimental values. Low‐lying vibrational energy levels of ZnH2, ZnD2, and HZnD are calculated on the three‐dimensional potential energy surface using the Lanczos algorithm, and found to be in good agreement with the available experimental band origins and the previous theoretical values. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010 相似文献
94.
M.G. Brik 《Journal of luminescence》2011,131(12):2642-2645
In the present paper, we report on consistent crystal field calculations of the Cr3+ ions energy levels in KAl(MoO4)2 using actual D3d site symmetry of the Cr3+ position and employing the exchange charge model (ECM) of the crystal field. In addition to the energy level calculations, the Huang-Rhys factor S=5.7 and effective phonon energy ?ω=268 cm-1 were evaluated in the single configurational coordinate model. Detailed treatment of the microscopic crystal field effects in the ECM framework allowed to obtain analytical dependence of the crystal field strength 10Dq on the Cr-O interionic distance and extracting from it the values of some parameters of the electron-vibrational interaction (EVI) in the KAl(MoO4)2:Cr3+ system. All obtained results are compared with experimental data and discussed; agreement between the calculated and experimental parameters is good. 相似文献
95.
We have presented the behavior of a shallow donor impurity with binding energy in cylindrical-shaped GaAs/Ga0.7Al0.3As quantum well wires under high hydrostatic pressure values. Our results are obtained in the effective mass approximation using the variational procedures. In our calculations, we have not considered the pressure related Γ−X crossover effects. The hydrostatic pressure dependence on the expectation value of ground state binding energy is calculated as a function of wire radius at selected temperatures. We have also discussed the effects of high hydrostatic pressure and temperature on some physical parameters such as effective mass, dielectric constant, and barrier height. A detailed analysis of these calculations has proved that the effective mass is the most important parameter, which explains the dependency of donor impurity binding energies on the high hydrostatic pressure values. 相似文献
96.
《Journal of Coordination Chemistry》2012,65(11):2021-2027
Results of quantum-chemical calculations of MCl4–C6H5COCl (M=Si, Ge, Sn) systems of 1?:?1 composition using RHF/3-21?G* and MP2/3-21?G* levels as well as those of 1?:?2 composition using the RHF/3-21?G* level have been represented. MCl4?←?C6H5COCl complexes of 1?:?1 composition are energetically more advantageous. They are formed in solid state provided that the M···O distance in individual systems is considerably less than the sum of van der Waals radii of M and O and their total energies are appreciably less than the sum of total energies of components. These conditions are realized only for M=Sn. In systems of 1?:?2 compositions, calculated M···O distances are practically equal to the sum of covalent radii of M and O. Nonetheless, complexes with such composition are not formed in solid state. Total energy of the system which is lower than the sum of its components’ energies is not an indispensable condition for complex formation. The 35Cl nuclear quadrupole resonance (NQR) frequencies and asymmetry parameters of the electric field gradient at the 35Cl nuclei have been evaluated using the results of ab initio calculations. 相似文献
97.
只有紧跟时代步伐,牢牢把握青年大学生的思想脉搏,不断创新我们教育培养工作的方法、措施,有的放矢,力求实效,才能促进大学生入党积极分子的健康成长,为高校学生党员发展工作提供源头活水。 相似文献
98.
刘云翔 《长春工程学院学报(自然科学版)》2001,2(2):63-64
提出了一种基于基本Fuzzy控制器基础上更好地模拟人的操作经验来改善控制性能的一种高精度Fuzzy控制器的设计方法 ,针对将语言变量量化出相应的等级引起的误差 ,采用了加权方法进行处理 ,提高了控制器的精度 ,有一定的实用价值 相似文献
99.
五像限法太阳自动跟踪仪 总被引:2,自引:0,他引:2
介绍由两心圆组成的等面积五像限光测量装置工作原理,即当光线与光电池垂直时其投影光斑经过一透镜后正好安全覆盖五片光电池,当光线与光电池成一夹角时,其投影光斑必然发生偏移,将光主在光电池上的偏移转移成光电流差值的变化,实现装置自动跟踪太阳。 相似文献
100.