Ru(0001)表面氮分子和钡原子的相互作用  

Interactions between nitrogen molecules and barium atoms on Ru(0001) surface

作　　者：赵新新[1] 陶向明[2] 宓一鸣[1] 徐红霞[1] 汪丽莉[1] 任莉[1] 谭明秋[2] 

机构地区：[1]上海工程技术大学基础教学学院,上海201620 [2]浙江大学物理系,杭州310027

出　　处：《原子与分子物理学报》2011年第3期511-518,共8页Journal of Atomic and Molecular Physics

基　　金：上海市教育委员会科研创新项目(10YZ172);浙江省教育厅科研项目(Y200804278)

摘　　要：本文采用密度泛函理论方法研究了Ru(0001)表面氮分子和钡原子的相互作用.计算结果表明,钡原子的作用弱化了氮分子键.氮分子键长从Ru(001)—N_2表面的0.113 nm伸长至Ru(001)—N_2/Ba表面的0.120 nm;分子的拉伸振动频率从2221 cm^(-1)减小到1746 cm^(-1);氮分子得到的电荷数从清洁表面的0.3e增加到1.1 e.电荷从钡原子6s轨道向钌原子4d轨道转移,转移电荷增强了氮分子2π空轨道和钌原子4d轨道间的杂化作用,导致5σ分子轨道和dπ杂化轨道发生极化.轨道极化使分子电偶极矩增加了约—0.136 eA.金属钡在Ru(0001)表面氮分子活化过程中具备电子型助催剂的特征.We had performed first principles calculations on interactions between nitrogen molecules and barium atoms on Ru（0001） surface using density function theory methods. It was shown that effects of barium atoms weakened the bond strength of nitrogen molecules. The bond length of nitrogen molecule increased from 0. 113 nm on Ru（001）-N2 to 0. 120 nm on Ru（001）-N2/Ba surface. While stretch vibrational frequency of nitrogen molecule decreased from 2222 cm-1 to 1746 cm-1 and charge transfer toward nitrogen molecule increased from 0.3 e to 1.1 e. Charge was mainly translated from 6s orbitals of barium atoms to 4d orbitals of substrate, which enhanced the hybridization between 4d and 2π orbitals and increased the dipole moment of 5a and dπ orbitals of nitrogen molecule. The molecular dipole moment of nitrogen molecule was increased by -0. 136 eA. It was suggested that barium had some characters to be an electronic promoter on the process of activating nitrogen molecules on Ru（0001） surface.

关 键 词：密度泛函理论 Ru(0001)表面 吸附能 分子振动 表面电子结构 

分 类 号：O643[理学—物理化学] O647[理学—化学]