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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Electronic and Molecular Structures of the CeB6 Monomer
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Electronic and Molecular Structures of the CeB6 Monomer

机译：CEB 6 单体的电子和分子结构

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The electronic and molecular structure of the CeB_(6) molecular unit has been probed by anion PE spectroscopy and DFT calculations to gain insight into structural and electronic relaxation on edge and corner sites of this ionic material. While boron in bulk lanthanide hexaboride materials assumes octahedral B_(6)~(3–) units, the monomer assumes a less compact structure to delocalize the charge. Two competitive molecular structures were identified for the anion and neutral species, which include a boat-like structure and a planar or near-planar teardrop structure. Ce adopts different orbital occupancies in the two isomers; the boat-like structure has a 4f superconfiguration while the teardrop favors a 4f 6s occupancy. The B_(6) ligand in these structures carries a charge of ?4 and ?3, respectively. The teardrop structure, which was calculated to be isoenergetic with the boat structure, was most consistent with the experimental spectrum. B_(6)-local orbitals crowd the energy window between the Ce 4f and 6s (HOMO) orbitals. A low-lying transition from the B-based orbitals is observed slightly less than 1 eV above the ground state. The results suggest that edge and corner conductivity involves stabilized, highly diffuse 6s orbitals or bands rather than the bulk-favored 5d band. High-spin and open-shell low-spin states were calculated to be very close in energy for both the anion and neutral, a characteristic that reflects how decoupled the 4f electron is from the B_(6) 2p- and Ce 6s-based molecular orbitals.
机译：CEB_（6）分子单元的电子和分子结构已被阴离子PE光谱和DFT计算探测，以深入了解该离子材料的边缘和角部位的结构和电子松弛。虽然散装镧系元素六硼化物材料呈八面体B_（6）〜（3-）单位，但单体呈现不太紧凑的结构，以将电荷划分。针对阴离子和中性物种鉴定了两种竞争分子结构，其包括船状结构和平面或近平面泪珠结构。 CE采用两名异构体的不同轨道占用;船上的结构具有4F的超级配置，而泪滴有利于4F 6S占用。这些结构中的B_（6）配体分别用于α4和α3的电荷。用船舶结构计算的泪珠结构是与船结构的异射性，最符合实验光谱。 B_（6）-local轨道在CE 4F和6S（HOMO）轨道之间的能量窗口中挤压。从B基轨道的低位过渡观察到在地面上方略小于1eV。结果表明，边缘和拐角电导率涉及稳定，高度漫射6S轨道或频带，而不是散装的5D频段。计算出高旋转和开壳低旋转状态，以非常接近电阴和中性的能量，这是反映4F电子如何从B_（6）2P和CE 6S的分子分离的特征轨道。

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