CO在Pt／Si和Pd／Si上的化学吸附

Co Chemisorption On Pd/Si and Pt/Si

本文根据单电子化学吸附理论，利用格林函数方法和复能积分技术，研究了ＣＯ在Ｐｔ／Ｓｉ和Ｐｄ／Ｓｉ上的化学吸附，用ｓｐ杂化轨道模型描述衬底，用紧束缚的ｄ轨道模型描述金属。计算结果表明：（１）化学吸附能随Ｓｉ上金属的层数增加而单调下降；（２）△ε＜０ｅＶ的杂质效应表现为使化学吸附减弱；△ε＞０ｅＶ的杂质效应表现为杂质位于表面第一层时加强了化学吸附，杂质位于其它层时减弱了化学吸附。

In terms of the one-electron chemisorption theory,the chemisorption properties ofCO on Pd/Si and Pt/Si are investigated by using the Green's function method andcomplex-energy-plane intergation techmque. The substrate Si is modeled by sp-hybrid orbital chainand the metal is modeled by d-orbital chains within the limts of the one dimensional TBA,The resultsshow that(1)in the absence of impurities,the chemisorption energy of CO on Pd/Si(Pt/Si)decreaseswith increasing of the metal thickness and gradually approaches the value of CO on bulk-metal,andthe threshold point is reached as metal is in 5 layers.(2)in the case of impurities introdueed,thechemisorption is weakened if △ε< 0ev;the chemisornti on is strengtbened(weakened)when the theimpurity is located in the metal surface(others)if △ε>0eV.