多重散射团簇方法对吸附系统SO_2/Ag(110)的理论分析

MULTIPLE-SCATTING CLUSTER STUDIES OF SO_2 ADSORBED ON Ag(110) 

利用多重散射团簇方法 (MSC)对吸附系统SO2 /Ag(110 )的S原子K边X射线吸收精细结构谱 (NEXAFS)作了理论分析 .研究表明 ,覆盖度为 0 5时 ,吸附的SO2 的S—O键长比气体状态时增长了 (0 0 14± 0 0 0 6 )nm ,OSO键角减小了 15°± 5°;SO2 分子的S原子处于芯位 ,但两个O原子处于不对称的位置 ;分子平面与 (110 )的夹角约为5 2° ,同时分子平面相对衬底表面法线有一小角度的倾斜 .MSC计算证实了该吸附系统存在一介于π 与σ 态中间的共振结构 ,这是由SO2

The multiple\|scattering cluster method (MSC) has been used to study theoretically the sulphur K \|edge NEXAFS of SO\-2 adsorbed on the Ag (110) at 1/2 coverage.It is shown that SO\-2 is adsorbed on the Ag (110) with S atom sitting in the hollow site and two O atoms being in an asymmetric geometry,the molecular plane is rotated from the (110) by approximately 52° and tited slightly towards the substrate.Compared to the case of the gas phase SO\-2,the O—S intramolecular bond length is elngated by (0 014±0 006)nm and the OSO bond angle is reduced by 15°±5° after adsorption.The resonance located between π\+* and σ\+* is proved to be induced by the interaction between SO\-2 and substrate.