密度泛函理论研究CO与Ni_n(n=1—6)团簇的相互作用

Density functional study of the interaction of CO with nickel clusters

采用密度泛函理论对CO吸附在镍团簇表面进行了系统研究.结果表明,NinCO团簇的最低能量结构是在Nin团簇最低能量结构的基础上吸附CO生长而成,CO的吸附没有改变Nin团簇的结构;CO分子在Nin团簇表面发生的是非解离性吸附,与优化的CO键长(0.1138 nm)相比,吸附后C—O键长变长(0.1180—0.1214 nm),表明吸附后C—O键被削弱,CO分子被活化.自然键轨道分析表明,CO分子只与最近邻的Ni原子发生相互作用;CO分子与Ni原子相互作用的本质是CO分子内的杂化轨道与Ni原子3d,4s,4p轨道相互作用的结果.

The adsorption of CO on the Nin cluster surfaces has been systematically investigated by density functional theory. The result indicates that the lowest energy structures of Nin CO are generated with CO being adsorbed on Nin clusters, and the lowest energy structures of Nin clusters are not changed by adsorbing CO molecule, The chemisorption of CO on Nin cluster surfaces belongs to non-dissociative adsorption. The increased theoretical CO bond length of 0.1180 - 0. 1214 nm （compared with 0.1138 nm） demonstrates the activation of the CO bond. Natural bond orbital analysis shows that the interaction between Ni atoms and CO molecule is primarily contributed by the hybridized molecular orbital within CO and 3d, 4s, 4p orbital of Ni atoms