中国物理B ›› 2018, Vol. 27 ›› Issue (6): 63102-063102.doi: 10.1088/1674-1056/27/6/063102

• ATOMIC AND MOLECULAR PHYSICS • 上一篇    下一篇

Structure, stability, catalytic activity, and polarizabilities of small iridium clusters

Francisco E Jorge, José R da Costa Venâncio   

  1. 1 Unidade Acadêmica de Física, Universidade Federal de Campina Grande, 58429-900 Campina Grande, Brazil;
    2 Departamento de Física, Universidade Federal do Espírito Santo, 29060-900 Vitoria, Brazil
  • 收稿日期:2017-11-12 修回日期:2018-03-13 出版日期:2018-06-05 发布日期:2018-06-05
  • 通讯作者: Francisco E Jorge E-mail:jorge@cce.ufes.br
  • 基金资助:
    Project supported by the CNPq,CAPES,and FAPES (Brazilian Agencies).

Structure, stability, catalytic activity, and polarizabilities of small iridium clusters

Francisco E Jorge1,2, José R da Costa Venâncio1   

  1. 1 Unidade Acadêmica de Física, Universidade Federal de Campina Grande, 58429-900 Campina Grande, Brazil;
    2 Departamento de Física, Universidade Federal do Espírito Santo, 29060-900 Vitoria, Brazil
  • Received:2017-11-12 Revised:2018-03-13 Online:2018-06-05 Published:2018-06-05
  • Contact: Francisco E Jorge E-mail:jorge@cce.ufes.br
  • Supported by:
    Project supported by the CNPq,CAPES,and FAPES (Brazilian Agencies).

摘要: At the second order Douglas-Kroll-Hess (DKH2) level, the B3PW91 functional in conjunction with the relativistic all-electron basis set of valence triple zeta quality plus polarization functions are employed to compute bond lengths, dissociation energies, vertical ionization potentials, and the highest occupied molecular orbital-lowest unoccupied molecular orbital energy gaps of the small iridium clusters (Irn, n ≤ 8). These results are compared with the experimental and theoretical data available in the literature. Our results confirm the theoretical predictions made by Feng et al. about the catalytic activities of the Ir4 and Ir6 clusters. From the optimized geometries, DKH2 calculations of static electric mean dipole polarizabilities and polarizability anisotropies are also carried out. It is the first time that the polarizabilities of small iridium clusters have been studied. For n ≤ 4, the mean dipole polarizabilities per atom present an odd-even oscillatory behavior, whereas from Ir5 to Ir8, they decrease with the cluster size increasing. The dependence of the polarizability anisotropy on the structure symmetry of the iridium cluster is verified.

关键词: B3PW91 functional, all-electron basis sets, DKH2 calculations, iridium clusters, polarizabilities

Abstract: At the second order Douglas-Kroll-Hess (DKH2) level, the B3PW91 functional in conjunction with the relativistic all-electron basis set of valence triple zeta quality plus polarization functions are employed to compute bond lengths, dissociation energies, vertical ionization potentials, and the highest occupied molecular orbital-lowest unoccupied molecular orbital energy gaps of the small iridium clusters (Irn, n ≤ 8). These results are compared with the experimental and theoretical data available in the literature. Our results confirm the theoretical predictions made by Feng et al. about the catalytic activities of the Ir4 and Ir6 clusters. From the optimized geometries, DKH2 calculations of static electric mean dipole polarizabilities and polarizability anisotropies are also carried out. It is the first time that the polarizabilities of small iridium clusters have been studied. For n ≤ 4, the mean dipole polarizabilities per atom present an odd-even oscillatory behavior, whereas from Ir5 to Ir8, they decrease with the cluster size increasing. The dependence of the polarizability anisotropy on the structure symmetry of the iridium cluster is verified.

Key words: B3PW91 functional, all-electron basis sets, DKH2 calculations, iridium clusters, polarizabilities

中图分类号:  (Relativistic corrections, spin-orbit effects, fine structure; hyperfine structure)

  • 31.15.aj
31.15.eg (Exchange-correlation functionals (in current density functional theory)) 36.40.-c (Atomic and molecular clusters)