排序方式: 共有1条查询结果,搜索用时 0 毫秒
1
1.
The valence charge density distribution for the icosahedral AlPdMn (i-AlPdMn) quasicrystal was obtained with the structure
factors of the nine strongest symmetry inequivalent reflections, which were refined by using the quantitative convergent beam
electron diffraction (QCBED) technique. It shows that the bonding charge is localized. The enhanced charge density in the
middle of the aluminum-transition-metal (Al-TM) bond shown in the valence charge density distribution is the characteristic
of covalent bonding. Assuming that the shape of an atom is a sphere with covalent radius, the number of electrons that each
atom gains or loses in 55 different pseudo-Mackay clusters (PMCs) was calculated based on the obtained valence charge density
distribution. It indicates that almost all the atoms lose electrons except a few Pd atoms that are in some particular shells.
It also shows that the atoms of an identified element could have different valences because of chemically and/or structurally
different local environments in which the atoms situate. Regardless of the topology and chemical occupancy, the number of
valence electrons per atom in a cluster is close to 1.69. This strongly suggests that the pseudo-Mackay clusters are stabilized
at a certain electron concentration.
Biography: YU Fengmei (1965–), female, Professor, Ph.D., research direction: quasicrystal physics. 相似文献
1