H原子在Au_xAg_(1-x)表面上的化学吸附

Hydrogen Chemisorption on Au_xAg_(1-x)

采用相干势近似（CPA）和Einstein-Schrieffer化学吸附理论计算了H原子在AuxAg1-x合金表面上的化学吸附能．计算结果表明，化学吸附能△E随着Au体浓度Xb的增加而减小；Ag在清洁合金表面的偏析导致化学吸附能△E增加；化学吸附诱导表面偏析的影响在化学吸附中不能被忽略，化学吸附能随H原子覆盖度θ的增大而减小．

The coherent-potential approximation (CPA) and the chemisorption theory ofEinstein-Schrieffer are used to calculate the chemisorption energy of hydrogen on the AuxAg1-x disordered binary alloy. The calculated results show that the chemisorption en ergy △E decreases with increasing the Au bulk conentration Xb, and the segregation of Ag at the clean alloy surface leads to an increase in △E. The effect of chemisorption -induced surface segregation cannot be neglected in chemisorption. The chemisorption energy decreases with the increase of the hydrogen coverage θ.