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

石川提出的确定镧系配合物同构系列的地面多重亚层结构的计算方法应用于几种具有代表性的镧系配合物。关于4f配合物电子结构的新信息导致镧系配合物的物理化学新方面如下。(1)测定了双（酞菁酸）镧系元素Pc_2Ln^-和三（二吡啶酸）镧系元素Ln（二吡啶酸）_3^<3->的配体场参数和基簇结构。首次从量子化学的角度定量地阐明了这些配合物的磁化率和核磁共振数据的温度依赖性。(2)测定了三（酞菁）双核镧系配合物Pc_3Ln_2的配体场参数。这就解释了配合物中两个镧系离子之间的f-f相互作用的性质。(3)单离子镧系化合物的SMM行为，Pc_2Tb^-和Pc_2Dy^-发现了更多的lex。(4) π自由基Pc_2Tb^0比阴离子配合物在更高的温度范围（10K）表现出SMM行为。在π-自由基SMM中，单个分子中存在S_z=(+1/2,-1/2)和J_z=(+6,-6)两种自旋体系，导致π- f相互作用产生这种显著的效应。(5)从实验和理论两方面阐明了f-f相互作用对双核铽配合物Pc_3Tb_2动力学磁性的贡献。(6)在亚开尔文范围内的磁化率测量表明，Pc_2Tb^-、Pc_2Dy^-和Pc_2Ho^-在磁化滞后曲线上呈现阶梯状结构。这些结构是由磁化的量子隧穿（QTM）引起的。(7)Ln(dipic)_3^<3->与奇数个4f-选举表现出显著的直流磁场依赖性。在1.7K以上10 ~ 10^3 Hz的交流磁场中，6种重镧系配合物均未表现出磁化滞后现象，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现象。少

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