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We applied periodic density-functional theory to investigate the adsorption of C2H2 on the Cu/Pt bimetallic and monometallic surfaces, including Cu-Pt-Pt and Pt-Cu-Pt representing the monolayer Cu on the Pt surface and subsurface Cu in the Pt surface, respectively. For the Pt(111) and Pt-Cu-Pt surfaces, C2H2 is preferentially a 3-fold "parallel-bridge" configuration, and a "μ-bridge" structure exists above the Cu(111) and Cu-Pt-Pt surfaces. The adsorption energy of C2H2 on these surfaces decreases in the order Pt(111) > Cu-Pt-Pt > Pt-Cu-Pt > Cu(111). The analysis of density of states, charge, and vibrational frequencies showed obviously weakening of the adsorbed C-C bond and high sp2 character on the carbon atom. Furthermore, when the top-layer compositions are equal, the nearer the EF d-band center is, the larger the C2H2 adsorption energy will be. 相似文献
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层状金属配位聚合物[{NiX2(bipy)}n](X=F,Cl,Br,I;bipy=4,4‘—bipy … 总被引:1,自引:0,他引:1
用紧束缚晶体轨道方法对层状金属配位聚合物「{NiX2(bipy)}n「(X=F,Cl,Br,I;bipy=4,4’-bipyridyl)进行了能带结构计算,并利用键向量方法对这一系列聚合物能带特征和成键性质进行了讨论。 相似文献
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Cu(100)表面吸附HCN和HNC的密度泛函研究 总被引:1,自引:0,他引:1
采用密度泛函方法,以原子簇Cul4为模拟表面,对氢氰酸(HCN)和异氰酸(HNC) 在Cu(100)表面上不同吸附位的吸附情况进行了研究.结果表明:HCN和HNC分别通 过原子N和C垂直吸附在表面上时,顶位是其最佳吸附位,且是吸附能为18.5kJ· mol^-1和42.6kJ·mol^-1的弱吸附,计算结果与实验相符.C—N(HCN)键或N—C (NHC)键偏离垂直的分子轴线的吸附体系均不稳定.顶位吸附时HCN和HNC分子的C- N键振动频率均发生蓝移. 相似文献
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本文报导了异羟肟酸类的正丁醇溶液从硝酸体系中萃取钇(Ⅲ)及混合稀土的研究。重点考察了苯甲酰异羟肟酸萃取钇(Ⅲ)的条件,当水相酸度为pH=4.5~5.5,萃取剂浓度为0.05mol/L,相比(Vo/Vw)为1:3时,获得最佳萃取效果。 相似文献
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The possible geometries of Fe(HCN)n+ (n = 1~6) compounds were studied by using DFT/UB3LYP/6-31G(2df) method. The structure and ground state of each fragmental ion are C∞v (4∑+ or 6∑+), D∞h(4∑g+), D3h (4A1'), C2v or Td or C3v (4A1), and D3h (4A1') or C4v( (2A1') sequentially with n = 1~5. For the compound Fe(HCN)6+, the possible geometry was not obtained. The sequential incremental interaction energy (-△(△E)), dissociation energy (△D0), enthalpy (-△(△H)) and Gibbs free energy (-△(△G)), and frequencies for HCN-Fe(HCN)n-1+ were also calculated, and the results are all in good agreement with the experiments. The bond length of Fe-N is lengthened with the increase of cluster size, and the strength of Fe+-N coordination bond varies nonmon- tonically as increasing the number of ligands. The Fe+-N bond of Fe(HCN)2+ is the strongest in all compounds. 相似文献