H原子在Al(111)和Ag(111)面上的吸附

本文用电荷自洽的EHT方法,研究了H原子在Al(111)和Ag(111)面上的吸附,结果指出:在Al(111)面上,H以原子状态吸附在某些对称位置上,它也能渗透到表面层中去,成为填隙原子;H₂分子在表面处发生解离吸附。在Ag(111)表面上,H原子有可能以分子状态吸附,H—H键平行于表面,这与高分辨率电子能量损失谱所得到的实验结果一致;但H₂分子在Ag(111)表面也可能发生解离吸附。 关键词：

STUDIES OF HYDROGEN ADSORPTION ON Al(111) AND Ag(111) SURFACES BY EHT METHOD

The hydrogen adsorption on Al(111) and Ag(111) surfaces have been studied by the charge self-consistent EHT method. It is shown that the H₂ molecule would dissociated on Al(111) surface, the H atom could be adsorbed at certain sites with symmetric geometry (such as the threefold, eclipsed, bridge and the atop sites), and H could penetrate into the surface layer and become an interstitial atom. However it is shown that the H₂ molecule can be adsorbed on Ag(111) surface with H-H bond paralled to the surface, this result seems to be in fairly good agreement with the result of high resolution electron-energy-loss spectra for H₂ on Ag at low temperature. In addition, when the temperature is high, the dissociative adsorption of H₂ on Ag(111) surface is also possible.The merit of the method used is discussed.