Is the uniform electron gas limit important for small Ag clusters? Assessment of different density functionals for Agn (n⩽4)

Abstract

Twenty-three density functional theory (DFT) methods, including the second- and the third-generation functionals, are tested in conjunction with two basis sets (LANL2DZ and SDD) for studying the properties of neutral and ionic silver clusters. We find that DFT methods incorporating the uniform electron gas limit in the correlation functional, namely, those with Perdew's correlation functionals (PW91, PBE, P86, and TPSS), Becke's B95, and the Van Voorhis-Scuseria functional VSXC, generally perform better than the other group of functionals, e.g., those incorporating the LYP correlation functional and variations of the B97 functional. Strikingly, these two groups of functionals can produce qualitatively different results for the Ag3 and Ag4 clusters. The energetic properties and vibrational frequencies of Ag(n) are also evaluated by the different functionals. The present study shows that the choice of DFT methods for heavy metals may be critical. It is found that the exact-exchange-incorporated PBE functional (PBE1PBE) is among the best for predicting the range of properties.

A Density-Functional Study on the Interaction of C2H Radical with Silver Clusters Agn0/-(n =1–4)

“…The perfectly linear structure contains a C≡C triple bond with r C≡C = 1.22 Å, C-Ag σ-bond with r C-Ag = 2.09 Å, and an Ag-Ag bond with r Ag-Ag = 2.67 Å. Our calculated Ag-Ag bond lengths in 2A and 2N are longer than the experimental value 2.53 Å and 2.61 Å in single Ag 2 cluster [41,42] due to the interaction between C 2 H radical with Ag 2 0/-cluster. The Ag atoms connected to C of C 2 H radical in 2A and 2N carry the net atomic charges of +0.22 and +0.38 |e|, respectively.…”

“…Distinctive similarities were also observed in the ground states of C 2v C 2 HAu 3 and C 2v C 2 HAu 3 - [29]. The Ag-Ag bond length in C 2 HAg 3 -(1A) is 2.77 or 2.78 Å, which is shorter than that in D 3h Ag 3 2+ (2.88 Å) [44] but longer than that in C 2v Ag 3 (2.67 Å) and D 3h Ag 3 -(2.69 Å) [42]. Similar to Au 3 triangular [29], Ag 3 triangular unit can serve as substituent to replace one H atom in C 2 H 2 to form the head-on coordinated C 2 HAg 3 -3A and C 2 HAg 3 3N.…”

The Nature of Transannular Interactions in E4N4 and E82+ (E = S, Se)

“…77 The poorer performance of BLYP and B3LYP in comparison with PBE and PBE0 can be rationalized with the fact that the LYP correlation functional does not obey the uniform electron gas limit: a correct limiting behavior for different density functionals has recently been shown to be important for the description of different types of bonding interactions such as metal-metal and agostic bonds. [78][79][80] However, it is not readily apparent why the GGA and hybrid versions of the PBEPBE functional lead to very large differences in the predicted E⋯E distances.…”

Influence of DFT-functional and basis set of functions on calculation results of the structural and energy properties of Ag2 molecular cluster

“…На сегодня разработано большое количество DFT-функционалов [8]. Теоретические исследования на разных уровнях теории струк-турных и электронных свойств нейтральных МК серебра проведены в работах [9][10][11]. Однако проблема выбора функционала для изучения структуры и других свойств МК переходных металлов, в том числе и серебра, недостаточна изучена.…”