团簇Aun+1-1、AunCr-1 (n=1-10)吸附CO的密度泛函理论研究

采用密度泛函理论对CO在阴离子团簇Aun+1-1、AunCr-1(n=1-10))表面的吸附做了系统研究.结果表明,团簇Aun+1CO-1、AunCrCO-1的基态结构是在团簇Aun+1-1、AunCr-1最低能量结构的基础上吸附CO形成; 吸附后的CO键长变长,振动频率减小,表明CO分子被活化;取值相同时，AunCrCO-1的平均结合能高，表明团簇Aun+1CO-1掺杂Cr后稳定性升高.HOMO-LOMO能隙结果表明Aun+1CO-1替代掺杂Cr原子后团簇的化学活性得到了提升,AunCrCO-1、Aun+1CO-1团簇能隙具有奇偶振荡的现象;轨道电荷分析表明CO与团簇相互作用实质是C原子与成键Au原子或Cr原子间转移电荷,CO在与团簇相互作用过程中O原子轨道电荷分布几乎没有发生变化.

Density functional study of interaction of CO with anion Cr-doped Gold clusters and anion Gold clusters

The adsorption of CO on the surfaces of anion Cr-doped gold clusters and anion gold clusters has been systematically investigated by density functional theory. The results indicate that the stable structures of AunCrCO-1 and Aun+1CO-1(n=1-10) are generated by CO being adsorbed on the lowest energy structures of AunCr-1 and . The increased CO bond length and the reduced CO vibration frequence demonstrate that the activation of the CO molecule. The average binding energy of AunCrCO-1 is higher indicating that the stability of Aun+1CO-1 is increased by Cr-doping.The energy gaps of AunCrCO-1 and Aun+1CO-1 clusters exhibit an odd-even oscillatory behavior,and the result show that the chemical activity of Aun+1CO-1 is improved by Cr-doping.The orbital charges layout indicate that the interaction between CO and AunCr-1 , is essentially contributed by the transfer of charges between C atom and Au atom or Cr atom which bonded to C atom, while the charges distribution of O atom hardly change during the interaction between CO and AunCr-1 and clusters .