LaNi_(4.5)Al_(0.5)储氢合金固溶相的密度泛函研究  

Density functional theory study on solid solution phase of LaNi_(4.5)Al_(0.5) hydrogen storage alloys

作　　者：陈东[1] 周理海[1] 余本海[1] 王春雷[1] 高涛[2] 张东玲[1] 

机构地区：[1]信阳师范学院物理电子工程学院,信阳464000 [2]四川大学原子与分子物理研究所,成都610065

出　　处：《中国有色金属学报》2007年第7期1160-1165,共6页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学-中国工程物理研究院联合基金(10276027)

摘　　要：基于密度泛函理论,采用全势线性缀加平面波方法(FLAPW),研究LaNi4.5Al0.5储氢合金固溶相α-LaNi4.5Al0.5H0.5和α-LaNi4.5Al0.5H1.0中H原子的占位、态密度和电子密度,分析了H原子的加入对固溶体电子结构和稳定性的影响。结果表明:从能量角度计算得到α-LaNi4.5Al0.5H0.5中H原子最可能占据靠近Al的6m位,α-LaNi4.5Al0.5H1.0中的两个H原子最可能占据6m和4h*位;随着H原子的增加,晶胞主要沿着c轴方向膨胀;Al和Ni,H之间的相互作用是合金含氢固溶体保持稳定的主要因素;态密度图中低能量区域的态密度越大固溶体越稳定;如果EF处于带隙的底部,则体系较稳定。计算结果与已有的实验结果非常一致。Based on the density functional theory （DFT） and full-potential linearized augmented plane wave （FLAPW） method, the hydrogen occupied sites, electron densities and densities of states were analyzed for the solid solution phase α-LaNi4.5Alo.5Ho.5 and α-LaNi4.5Al0.5H1.0. The hydrogen atom in α-LaNi4.5Al0.5H0.5 is found to prefer the 6m position near aluminum atom, the two hydrogen atoms in α-LaNi4.5Al0.5H0.5H1.0 are most likely to take the 6m and 4h＊ sites by total energy minimization calculation. The lattice expansion is mainly along the c axis. The interaction between aluminum and nickel, hydrogen plays a dominant role in the stability of LaNi4.5Al0.5Hx solid solution phase. The smaller the shift of EF towards higher energy region, the more stable the compounds will be. The calculated results are compared with the existent experimental data and discussed in light of previous works.

关 键 词：LaNi4.5Al0.5合金 密度泛函理论 线性缀加平面波方法(FLAPW) 固溶相 

分 类 号：TG139.7[一般工业技术—材料科学与工程]