基于密度泛函理论,采用总能量计算方法与结合超软赝势平面波函数方法,对LaNi4.5Mn0.5储氢合金及其氢化物的晶体几何结构进行了优化,计算了其相应的总体能量、晶体结构、能带结构、及态密度分布等,从理论上给出了其结构参数及性质。结果表明,锰取代3g位后合金晶胞略有膨胀,并伴随着晶体稳定性变差。LaNi4.5Mn0.5合金中EF附近的态密度贡献最主要来自La的p电子,以及Ni和Mn原子的d电子。
The method of total energy based on the density functional theory(DFT) was introduced in this paper,and the plane wave function was selected as the basis set in combination with Ultra-soft Pseudopotential technology.Both theoretical calculation and first principles analysis of LaNi4.5Mn hydrogen-storage alloy and its hydrid,in which Mn substituted for Ni at 3g sites,have been investigated.Total energy,crystal structure,energy band structure and electronic density of states were calculated.The results indicated that the crystal volume of the hydrogen storage alloy expanded slightly after Mn substituted at 3g site in LaNi5 alloys,along with the decrease of the crystal stability.The contribution of DOS near fermi energy(EF) for LaNi4.5Mn0.5 hydrogen storage alloy mainly due to p electron of La atom,d electron of Ni and Mn atom.