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Study of multinuclear f-electronic structures by a multidimensional non-linear optimization method

多维非线性优化方法研究多核f电子结构

基本信息

批准号：
15550046
负责人：
ISHIKAWA Naoto
金额：
$ 2.3万
依托单位：
Chuo University (2005)Tokyo Institute of Technology (2003-2004)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

The computational method which Ishikawa previously proposed for determination of sublevel structure of ground multiplets of isostructural series of lanthanide complexes was applied to several representative classes of lanthanide complexes. The new information about electronic structures of the 4f-complexes led to new physico-chemical aspects of lanthanide complexes as follows.(1)Ligand field parameters and ground multiplet structures have been determined for bis(phthalocyaninato)lanthanides Pc_2Ln^- and tris(dipicolinato)lanthanides Ln(dipic)_3^<3->. Temperature dependence of magnetic susceptibilities and NMR data of these complexes were quantitatively elucidated based on the quantum-chemical view for the first time.(2)Ligand field parameters of the tris(phthalocyaninato) dinulear lanthanide complexes Pc_3Ln_2 were determined. This led to the elucidation of the nature of the f-f interaction between the two lanthanide ions in the complexes.(3)SMM behavior of single-ionic lanthanide comp … More lex was discovered for Pc_2Tb^- and Pc_2Dy^-.(4)The π-radical Pc_2Tb^0 showed SMM behavior at even higher temperature range by 10K than the anionic complex. In the π-radical SMM, two spin system, S_z=(+1/2,-1/2) and J_z=(+6,-6) are present in a single molecule, leading to the pi-f interaction that yields this remarkable effect.(5)The contribution of the f-f interaction to the dynamical magnetism of the dinuclear terbium complexes Pc_3Tb_2 was elucidated both experimentally and theoretically.(6)Magnetic susceptibility measurements in the sub-kelvin range revealed that Pc_2Tb^-, Pc_2Dy^- and Pc_2Ho^- exhibit staircase-like structures in magnetization hysteresis curves. These structures are caused by the quantum-tunneling of magnetization (QTM).(7)Ln(dipic)_3^<3-> with odd numbers of 4f-elections exhibited significant dc-magnetic field dependences of ac susceptibilities. While none of the six heavy-lanthanide complexes showed magnetization lag from ac magnetic field of 10 - 10^3 Hz above 1.7K, the Dy, Er and Yb complexes with odd numbers of 4f-electrons exhibited the magnetization lag in a dc field. Less

用Ishikawa等人提出的计算方法计算了几类具有代表性的稀土配合物的等结构系列的基态多重态结构。关于4f-络合物电子结构的新信息导致了稀土络合物的新的物理化学方面如下：(1)测定了双(酞菁)稀土Pc_2Ln^-和三(Dipicolinato)稀土Ln(Dipic)_3^&lt；3-&gt；首次从量子化学的角度定量地解释了这些配合物的磁化率与温度的关系和核磁共振数据。(2)测定了三(酞菁)二缩稀土配合物Pc_3LN_2的配位场参数。从而阐明了配合物中两个稀土离子之间的f-f相互作用的性质。(3)单离子稀土复合…的SMM行为Pc_2Tb^-和Pc_2Dy^-中发现了更多的Lex。(4)π-自由基Pc_2Tb^0在比阴离子络合物更高的温度范围内表现出SMM行为。在π自由基分子模型中，单个分子中存在两个自旋系统，即S_z=(+1/2，-1/2)和J_z=(+6，-6)，从而产生了显著的pi-f相互作用。(5)从实验和理论上阐明了f-f相互作用对双核配合物Pc_3Tb_2的动态磁性的贡献。(6)在亚开尔文范围内的磁化率测量表明，Pc_2Tb^-，Pc_2DY^-和Pc_2Ho^-在磁滞曲线上呈现阶梯状结构。这些结构是由量子隧穿磁化(QTm)引起的。(7)具有奇数4f电子数的Ln(Dipic)3^&lt；3-gt；表现出显著的交流磁化率与直流磁场的关系。在1.7K以上，6个重稀土配合物在10-103 Hz的交流磁场范围内都没有表现出磁化滞后，而具有奇数个4f电子的Dy、Er和Yb配合物在直流磁场中表现出磁化滞后。较少