B3LYP calculations of cerium oxides

Abstract

In this paper we evaluate the performance of density functional theory with the B3LYP functional for calculations on ceria ͑CeO 2 ͒ and cerium sesquioxide ͑Ce 2 O 3 ͒. We demonstrate that B3LYP is able to describe CeO 2 and Ce 2 O 3 reasonably well. When compared to other functionals, B3LYP performs slightly better than the hybrid functional PBE0 for the electronic properties but slightly worse for the structural properties, although neither performs as well as LDA+ U͑U=6 eV͒ or PBE+ U͑U=5 eV͒. We also make an extensive comparison of atomic basis sets suitable for periodic calculations of these cerium oxides. Here we conclude that there is currently only one type of cerium basis set available in the literature that is able to give a reasonable description of the electronic structure of both CeO 2 and Ce 2 O 3 . These basis sets are based on a 28 electron effective core potential ͑ECP͒ and 30 electrons are attributed to the valence space of cerium. Basis sets based on 46 electron ECPs fail for these materials.

Volume-dependent electron localization in ceria

“…Another possibility to correct the improper electron self-interaction is to modify standard DFT functionals by adding some amount of nonlocal Fock exchange [13]. The use of such hybrid functionals is computationally more demanding than DFT+U and, in the case of reduced ceria, they do not provide a more accurate description than the DFT+U approximation [11].…”

“…There exist several theoretical works related to the problem of accurate description of the electronic structure and the physical properties of stoichiometric CeO 2 , reduced CeO 2−x , and Ce 2 O 3 oxides [1,4,[9][10][11]. Standard DFT using local density approximation (LDA) or generalized gradient approximation (GGA) for the exchange-correlation part of the energy functional fails to give a satisfactory description of the electronic structure of reduced ceria oxides.…”

A Macrocyclic Chelator That Selectively Binds Ln4+ over Ln3+ by a Factor of 1029

“…15,18,[31][32][33][34][35][36] Extended solids including CeO2 have also served as important test cases for evaluating whether accurate theoretical methodology can treat the 4f-electrons simply as part of the core, or whether a more demanding approach should be followed that allows the 4f-electrons to delocalize and participate in bonding. [37][38][39][40][41][42][43][44][45][46] Cerium intermetallics have been at the forefront of condensed matter physics and development of the Anderson impurity model for heavy fermion systems and Kondo insulators. 47 For example, Ce L3-and M5,4-edge XANES spectroscopic investigations of CeRu3, CeRh3, and CePt3 have provided evidence for 4f-electron delocalization, 20,23,[48][49] and L3-edge investigations of intermetallics such as CeCoIn5 have led to new understanding of their remarkable magnetic and superconducting properties.…”

Structures and vibrational spectroscopy of partially reduced gas-phase cerium oxide clusters

“…The local density approximation (LDA) and the generalized gradient approximation (GGA) lead to delocalized occupied Ce 4f states. 40 In contrast, calculations using hybrid functionals [41][42][43][44] or the DFT + U scheme [45][46][47] lead to localized f states on single Ce sites. For extended systems such as nanoparticles and surfaces, calculations using more demanding functionals, e.g., hybrid functionals are affordable only in exceptional cases.…”