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采用密度泛函理论(DFT)与耦合簇[CCSD(T)]相结合的计算方法对一系列二核铪氧簇合物Hf_2O_n~(–/0)(n=1~6)的电子结构进行了系统研究.通过密度泛函理论(DFT)计算对体系的势能面进行广泛的搜索,寻找能量最低的结构.采用广义Koopmans定理计算垂直电子逸出能(VDEs)并模拟阴离子光电子谱(PES).通过理论研究阐明了二核铪氧簇Hf_2O_n~(–/0)(n=1~6)结构演化规律,并利用分子轨道分析对二核铪氧簇Hf2On–(n=1~4)的化学成键和顺序氧化进行解释.自旋密度分析显示:除Hf_2O_5中性簇之外,其它富氧簇都存在多种类型的氧自由基:氧自由基、双自由基或超氧自由基.此外,研究发现Hf2O3中性簇中的定域Hf2+位容易与分子氧O2反应形成Hf_2O_5中性簇;Hf_2O_4~(–/0)簇合物与分子O_2作用形成Hf_2O_6~(–/0)簇合物,Hf_2O_4~(–/0)簇合物可以作为潜在的分子模型研究氧分子在铪氧化物上的活化.
The electronic structure of a series of Hf 2 O n ~ (- / 0) (n = 1 ~ 6) complexes was studied by the combination of density functional theory (DFT) and coupled cluster [CCSD (DFT), the potential energy surface of the system was searched extensively to search for the lowest energy structure.The generalized Koopmans theorem was used to calculate the vertical electron exit energies (VDEs) and simulate the anion photoelectron spectroscopy (PES) The structure evolution of Hf 2 O n ~ (- / 0) (n = 1 ~ 6) of the binuclear hafnium oxygen cluster has been elucidated theoretically, and the molecular orbital analysis has been used to study the HfO 2 n- (n = 1 ~ 4) Chemical bonding and sequential oxidation.The spin density analysis showed that there are many types of oxygen free radicals, oxygen free radicals, diradicals or superoxide free radicals in all other oxygen-rich clusters besides Hf 2 O 5 neutral clusters. In addition, it was found that the Hf2 + sites in the Hf2O3 neutral clusters easily react with the molecular oxygen O2 to form Hf2O5 neutral clusters. Hf2O4 ~ (- / 0) clusters and molecular O_2 form Hf_2O_6 ~ (- / 0) Hf_2O_4 ~ (- / 0) cluster can be used as a potential molecular model to study the activation of oxygen molecules on hafnium oxide.