-3Δ、-3Π、-3Σ-＋Ni—CO分子簇的从头算研究

Abstract

用从头算研究了d空穴位置不同对nI—CO成键机制的影响。结果表明，nI—CO键中σ/π接受作用的相对强弱，取决于nI—CO簇所处的能态。σ空间电子云较π空间电子云弥散，因而nI—CO簇的稳定性与σ空间电子云的排斥密切相关。随着nI4Pσ轨道上电子占据数的增加，nI—CO稳定性减弱。比较了分子簇nI—CO与nICO分子及CO/nI化学吸附体系之间的性质。

Ab initio methods are employed to study the inFluence of the d-hole position upon the Ni-CO bonding mechanism.The calculation results demonstrate that the relative importance of σ-donation and π-backdonation varies with the electronic states of Ni-CO.The electron cloud in σ subspace is more diFFuse than that in π subspace,thus the stability of Ni-CO is closely related to the electronic repulsion in σ subspace.With the increase of the Ni 4pσ occupation, the stability of Ni-CO decreases.Combinebd with the previous results,a comparison between Ni-CO molecular cluster and NiCO molecule, as well as CO/Ni chemisorption system, is given.