甲醛在Ir(111)面吸附的密度泛函理论研究  

Density Functional Theory Study of Formaldehyde Adsorption on Ir(111) Surface

作　　者：高守贵[1] 程春[2] 黄武英[2] GAO Shou-gui;CHENG Chun;HUANG Wu-ying(Department of Public Education,Heifei Preschool Education College,Hefei 230013;School of Physics and Electronic hfformation,Anhui Normal University,Wuhu 241000 Anhui,)

机构地区：[1]合肥幼儿师范高等专科学校基础部,合肥230013 [2]安徽师范大学物理与电子信息学院,安徽芜湖241000

出　　处：《合肥学院学报（综合版）》2018年第2期16-18,43,共4页Journal of Hefei University：Comprehensive ED

摘　　要：采用密度泛函理论对甲醛在Ir(111)表面top,bridge,fcc和hcp位的吸附模型进行了构型优化和振动频率分析。结果表明,甲醛在Ir(111)表面的最稳定的吸附构型是O原子和C原子分别与各自最邻近的Ir原子成键,整个甲醛分子像座桥搭在这两个Ir原子的上方,C-O键与Ir原子表面法线呈86.0°的倾角。该稳定的吸附构型为η~1-C-η~1-O构型,吸附能大小为0.78e V。通过对比吸附前后甲醛的振动频率,发现吸附后-CH2的对称与反对称伸缩振动频率均发生了蓝移,而C-O键的振动频率发生红移,说明了吸附过程中CH_2O的C-O键被活化。The first-principles density functional theory（ DFT） are used to investigate the adsorption of formaldehyde on Ir（ 111） surface at the top,bridge,fcc and hcp sites. The adsorption equilibrium geometry and the frequencies of vibration are analyzed. The results show that the most stable adsorption configuration of CH2O is O and C respectively bond with their nearest Ir atoms,formaldehyde molecule likes a bridge above the two Ir atoms,and the angle between C-O axis and the normal line of the surface is 86. 0°. This geometry is η^1-C-η^1-O and the adsorption energy for CH2O on Ir（ 111） is 0. 78 e V. According to the vibration frequencies before and after the adsorption of CH2O,the vibration frequencies of C-O bond has a red shift,which indicates that C-O bond scission occur for the decomposition of formaldehyde. But the symmetry and antisymmetry stretching vibration frequencies of CH2 have blue shifts.

关 键 词：甲醛 Ir(111)表面 吸附 密度泛函理论 

分 类 号：O552[理学—热学与物质分子运动论]