Hybrid density functional study of small Rhn(n=2−15)clusters

Abstract

The physical properties of small rhodium clusters, Rh n , have been in debate due to the shortcomings of density functional theory (DFT). To help in the solution of those problems, we obtained a set of putative lowest energy structures for small Rh n (n = 2-15) clusters employing hybrid-DFT and the generalized gradient approximation (GGA). For n = 2-6, both hybrid and GGA functionals yield similar ground-state structures (compact), however, hybrid favors compact structures for n = 7-15, while GGA favors open structures based on simple cubic motifs. Thus, experimental results are crucial to indicate the correct ground-state structures, however, we found that a unique set of structures (compact or open) is unable to explain all available experimental data. For example, the GGA structures (open) yield total magnetic moments in excellent agreement with experimental data, while hybrid structures (compact) have larger magnetic moments compared with experiments due to the increased localization of the 4d states. Thus, we would conclude that GGA provides a better description of the Rh n clusters, however, a recent experimental-theoretical study [Harding et al., J. Chem. Phys. 133, 214304 (2010)] found that only compact structures are able to explain experimental vibrational data, while open structures cannot. Therefore, it indicates that the study of Rh n clusters is a challenging problem and further experimental studies are required to help in the solution of this conundrum, as well as a better description of the exchange and correlation effects on the Rh n clusters using theoretical methods such as the quantum Monte Carlo method.

σ-Holes on Transition Metal Nanoclusters and Their Influence on the Local Lewis Acidity

“…Supplementary Materials: The following are available online at www.mdpi.com/2073-4352/7/7/222/s1, Figure S1: V S (r), E S (r) and the favored H 2 O adsorption structure for Rh 13 at the decatet spin-state; Table S1: spin multiplicity and <S 2 > expectation values for the Pt 4 and TM 8 nanoclusters; Table S2: spin multiplicity and <S 2 > expectation values for the TM 13 nanoclusters; Table S3: spin projection corrected and non-corrected H 2 O interaction energies for Ir 13 and Rh 13 ; Table S4: site-resolved H 2 O adsorption data, V S,max , and E S,min for all TM 13 nanoclusters; Table S5: the number of V S,max , and E S,min as well as the s-, d-and p-occupation for Rh 13 at the decatet spin-state; Table S6: site-resolved H 2 O adsorption data, V S,max , and E S,min for Rh 13 at the decatet spin-state; additional computational data for Figures 1 and 3; optimized coordinates; supplementary references [60][61][62][63][64][65][66][67][68][69][70][71][72].…”

Ethanol and Water Adsorption on Transition-Metal 13-Atom Clusters: A Density Functional Theory Investigation within van der Waals Corrections

“…[49][50][51][52][53][54] Thus, with the aim to improve our atomistic understanding and to obtain possible new pGMC using the all-electron FHI-aims implementation, we optimized about 60 atomic configurations for each TM 13 system, which includes well-known structures such as the doublesimple cubic (DSC), icosahedral (ICO) with I h symmetry, cuboctahedral (CUB) with O h symmetry, hexagonal bilayer (HBL) and buckled-biplanar (BBP) with C 3v symmetry. Furthermore, it in-3 Figure 1: Putative global minimum configurations (pGMC) for water, ethanol (gauche), Ni 13 , Pd 13 , Pt 13 , Cu 13 , Ag 13 , and Au 13 (two-dimensional pGMC structure -pGMC2D) clusters.…”

Structural formation of binary PtCu clusters: A density functional theory investigation

“…Our strategy is based on the observation that the atomic structure of an alloy cluster may be derived from the parent unary compounds [63], given that the structural properties of binary systems follow an intermediate behaviour in relation to the unary ones [64]. The following steps were performed: (i) A set of lowest and high energy configurations were obtained from total energy calculations and literature [6,65] for the Pt m and Cu m clusters ðm ¼ 2 À 14Þ, which are composed by a diversified set of 2D and 3D structures. The number of calculated configurations for the unary case was around 4 m, e.g., about 56 configurations for m ¼ 14.…”

“…For the past decades binary transition-metal (TM) clusters have attracted great interest [1] due to their unique structural, electronic, magnetic, and reactivity properties [2,3], which can be tuned by changing the number of atoms, composition, and charge states [4][5][6]. This fact opens the possibility for a wide range of technological applications, such as magnetic storage [7][8][9][10], and heterogeneous catalysis [2,[11][12][13][14].…”