LaNi_(4.5)Ga_(0.5)-H的电子结构和氢原子微观组态
The Electronic Structure and Hydrogen Microarrangements of LaNi_(4.5)Ga_(0.5)-H Systems
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摘要: 采用全势线性缀加平面波(FP-LAPW)方法研究了LaNi4.5Ga0.5Hy(y=1.0,1.5)的晶体结构,电子结构和氢原子的微观组态.计算基于H-H间的距离不小于2.1的准则,采用结构优化和内坐标驰豫并通过计算氢原子占据不同格位时LaNi4.5Ga0.5Hy的总能量得出氢原子最可能占据的位置.研究发现氢原子优先占据6m,12n*和3f位,4h格位没有氢原子占据.由于晶胞膨胀导致Ni-d带变窄,Ga原子的加入引起费米能级处态密度的降低,H原子的作用则相反.H和Ni,Ga之间的相互作用是LaNi4.5Ga0.5Hy固溶体保持稳定的主要因素.费米能级EF向高能区域移动的越少体系越稳定.Abstract: The crystal structures,electronic structures and hydrogen occupatied sites of LaNi4.5Ga0.5Hy(y=1.0,1.5)have been investigated using all-electron FP-LAPW method.Their equilibrium structures have been determined based on the calculated relative stabilities of hydrogen occupation sites in LaNi4.5Ga0.5Hy and the rule of H-H separation to be no less than 2.1 ,as well as the full optimization.The hydrogen atoms were found to prefer the 6m,12nand 3f sites.A narrowed Ni-d band was found due to the lattice expansio...
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