化学学报 ›› 2016, Vol. 74 ›› Issue (12): 1009-1017.DOI: 10.6023/A16090505 上一篇    

所属专题: 聚集诱导发光

研究论文

二核铪氧簇Hf2On-/0(n=1~6)的电子性质与结构演化的理论研究

陈仕芳a, 陈文杰b, 王彬a, 章晓斌a, 黄昕a,c, 章永凡a,c   

  1. a 福州大学化学学院 福州 350116;
    b 泉州师范学院化工与材料学院 泉州 362000;
    c 福建省理论与计算化学重点实验室 厦门 361005
  • 收稿日期:2016-09-21 出版日期:2016-12-15 发布日期:2016-12-05
  • 通讯作者: 章永凡 E-mail:zhangyf@fzu.edu.cn
  • 基金资助:

    项目受国家自然科学基金(Nos.21371034,21301030,21373048和21603117)资助.

Theoretical Study on Electronic Properties and Structural Evolution in Hf2On-/0 (n=1~6) Clusters

Chen Shifanga, Chen Wenjieb, Wang Bina, Zhang Xiaobina, Huang Xina,c, Zhang Yongfana,c   

  1. a College of Chemistry, Fuzhou University, Fuzhou 350116;
    b College of Chemical Engineering and Material, Quanzhou Normal University, Quanzhou 362000;
    c Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, Xiamen 361005
  • Received:2016-09-21 Online:2016-12-15 Published:2016-12-05
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Nos. 21371034, 21301030, 21373048 and 21603117).

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Hf2On-/0n=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Hf2On-/0n=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Hf2O5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Hf2O5中性簇;Hf2O4-/0簇合物与分子O2作用形成Hf2O6-/0簇合物,Hf2O4-/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.

关键词: 铪氧簇合物, 密度泛函理论, 耦合簇理论, 自由基, 模拟光电子谱

Extensive density functional theoretical (DFT) and ab initio[CCSD (T)]calculations were combined to investigate the geometric and electronic structure of a series of dinuclear hafnium oxide clusters,Hf2On-/0(n=1~6).DFT calculations were performed to search for the lowest energy structures for both the anionic clusters and the neutral counterparts.The search for the global minima was performed using analytical gradients with the Stuttgart relativistic small core potential and the valence basis sets augmented with two f-type and one g-type polarization functions for Hf and the aug-cc-pVTZ basis set for oxygen.The relative energies of the low-lying structures (within ca.0.35 eV) were further evaluated via single-point calculations at the coupled cluster[CCSD (T)]level with the Hf/Stuttgart+2f1g/O/aug-cc-pVTZ basis sets at the B3LYP geometries.Generalized Koopmans' theorem (GKT) was applied to predict VDEs and simulate the anion photoelectron spectra (PES).The trends of structural evolution and the behavior of sequential oxidation of the Hf2On-(n=1~6) clusters were observed.For the anionic species,starting from the C2v triangular structure Hf2O-,the next O atom in the Hf2O2- cluster was again bridge-bonded,forming a rhombus structure.The third O atom occupied the terminal site.The fourth O atom favored the bridging site and the fifth O atom occupied the terminal site.In Hf2O6-,the additional O atom was bonded to a terminal site.Molecular orbital analyses were performed to elucidate the chemical bonding and the structural evolution in Hf2On-(n=1~4) clusters.Spin density analyses revealed oxygen radical,diradical and superoxide characters in the oxygen-rich clusters,except for the singlet Hf2O5 cluster.We showed that Hf2O3 contains a localized Hf2+ site,which can readily react with O2 to form the Hf2O5 cluster.The Hf2O6- and Hf2O6 clusters,which can be viewed to be formed by the interaction of Hf2O4-/0 and O2,may be utilized as molecular models to understand dioxygen activation on Hf2O4- and Hf2O4 clusters.

Key words: hafnium oxide cluster, DFT, CCSD (T), radical, simulated PES