密度泛函理论研究Hg与Auqn(n=1—6, q=0,+1,-1) 团簇的相互作用

采用密度泛函理论中的广义梯度近似对Hg与小团簇Au ^q_n (n=1—6, q=0, +1, -1)的相互作用进行了系统研究. 结果表明,除Au₅^+,-团簇外,前线分子轨道理论可以成功预测大部分Au _n Hg ^q 复合物的最低能量结构. Au_n团簇对Hg的吸附受团簇尺寸大小和团簇所携带电荷的影关键词：密度泛函理论汞金团簇吸附能

Density functional study of interation of Hg with small gold clusters

Elemental mercury (Hg) adsorptions on small neutral, cationic and anionic gold clusters, Au^q_n (n=1—6, q=0, +1, -1), are systematically investigated by using the density functional theory(DFT) in the generalized gradient approximation. The result shows that the frontier molecular orbital theory (FMOT) is useful for predicting the favorable binding configurations of Hg adsorbed on neutral and charged Au_n clusters. Most of the lowest energy Au_nHg complexes can be successfully predicted. The size and the charge state of the clusters have strong influence on the adsorption of Hg on gold clusters. The adsorption energy on the neutral clusters reaches a local maximum at n=4, which is about 0.661eV. The adsorption energies for cationic clusters decrease with cluster size increasing, although there is a local peak at n=5. Similarly, for anionic clusters, the adsorption energies decrease with cluster size, except for n=3. The adsorption energies on the cationic clusters are generally stronger than those on the neutral and anionic clusters. For the lowest energy Au_nHg complexes, an approximate linear correlation between the adsorption energy and the Mulliken charge on adsorbed Hg is found. The more the charges transfer to the cluster, the higher the adsorption energy is.