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arXiv 1502.05285cond-mat.mtrl-sci
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富勒烯polymer Li4 C60的结构和动力学的中子散射研究

Structure and dynamics of the fullerene polymer Li4 C60 studied with neutron scattering

S. Rols, D. Pontiroli, C. Cavallari, M. Gaboardi, M. Aramini, D. Richard, M. R. Johnson, J. -M. Zanotti, E. Suard, M. Maccarini, M. Ricco

摘要:

用中子衍射和中子能谱研究了超离子导体Li_4C_(60)的二维聚合物结构和晶格动力学。这种化合物的独特的键合结构通过分子间键所涉及的碳原子的精确定位而得到明确证实。通过从头算晶格动力学计算和非弹性中子散射实验揭示了该相的光谱特征。中子观测值被发现是在非常好的协议与模拟预测的部分电荷转移从Li原子的C60笼。在实验光谱中没有与一类Li原子相关的定义明确的谱带,这表明即使在最低温度下,这种物质也不是有序的。计算预测一个不稳定的Li亚晶格在200 K的温度下,我们涉及到这个系统的大离子扩散系数。这种特异性进行了讨论的低频光学模式的锂离子的聚合物的软结构之间的耦合。

英文摘要:

The two-dimensional polymer structure and lattice dynamics of the superionic conductor Li4 C60 are investigated by neutron diffraction and spectroscopy. The peculiar bonding architecture of this compound is definitely confirmed through the precise localisation of the carbon atoms involved in the intermolecular bonds. The spectral features of this phase are revealed through ab-initio lattice dynamics calculations and inelastic neutron scattering experiments. The neutron observables are found to be in very good agreement with the simulations which predict a partial charge transfer from the Li atoms to the C60 cage. The absence of a well defined band associated to one category of the Li atoms in the experimental spectrum suggests that this species is not ordered even at the lowest temperatures. The calculations predict an unstable Li sublattice at a temperature of 200 K, that we relate to the large ionic diffusivity of this system. This specificity is discussed in terms of coupling between the low frequency optic modes of the Li ions to the soft structure of the polymer.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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