Interaction trends between single metal atoms and oxide supports identified with density functional theory and statistical learning

2018 ◽  
Vol 1 (7) ◽  
pp. 531-539 ◽  
Author(s):  
Nolan J. O’Connor ◽  
A. S. M. Jonayat ◽  
Michael J. Janik ◽  
Thomas P. Senftle
Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1281
Author(s):  
Zikri Altun ◽  
Erdi Ata Bleda ◽  
Carl Trindle

An atom trapped in a crystal vacancy, a metal cage, or a fullerene might have many immediate neighbors. Then, the familiar concept of valency or even coordination number seems inadequate to describe the environment of that atom. This difficulty in terminology is illustrated here by four systems: H atoms in tetragonal-pyramidal rhodium cages, H atom in an octahedral cobalt cage, H atom in a MgO octahedral hole, and metal atoms in C20 fullerenes. Density functional theory defines structure and energetics for the systems. Interactions of the atom with its container are characterized by the quantum theory of atoms in molecules (QTAIM) and the theory of non-covalent interactions (NCI). We establish that H atoms in H2Rh13(CO)243− trianion cannot be considered pentavalent, H atom in HCo6(CO)151− anion cannot be considered hexavalent, and H atom in MgO cannot be considered hexavalent. Instead, one should consider the H atom to be set in an environmental field defined by its 5, 6, and 6 neighbors; with interactions described by QTAIM. This point is further illustrated by the electronic structures and QTAIM parameters of M@C20, M=Ca to Zn. The analysis describes the systematic deformation and restoration of the symmetric fullerene in that series.


2010 ◽  
Vol 21 (12) ◽  
pp. 1469-1477 ◽  
Author(s):  
M. SAMAH ◽  
B. BOUGHIDEN

Structures, binding energies, magnetic and electronic properties endohedrally doped C 20 fullerenes by metallic atoms ( Fe , Co , Ti and V ) have been obtained by pseudopotential density functional theory. All M @ C 20, except Co @ C 20, are more stable than the undoped C 20 cage. The magnetic moment values are 1 and 2μB. These values and semiconductor behavior give to these compounds interesting feature in several technological applications. Titanium doped C 20 has a same magnetic moment than the isolated Ti atom. Hybridization process in the Co doped C 20 fullerene is most strong than in other doped cages. Electrical and magnetic dipoles calculated in the iron doped C 20 are very strong compared with other clusters.


Author(s):  
N. K. Das ◽  
K. Rigby ◽  
N. H. de Leeuw

Density functional theory calculations have been used to study the incorporation of helium in perfect and defect-containing palladium tritides, where we have calculated the energetics of incorporation and the migration behaviour. Helium atoms preferably occupy the octahedral interstitial and substitutional sites in the perfect and Pd vacancy-containing tritides, respectively. The energetics reveal that helium clusters can form in the lattice, which displace the Pd metal atoms. The defective lattice shows less expansion compared with the perfect lattice, which can accommodate the helium less easily. The path from octahedral–tetrahedral–octahedral sites is the lowest energy pathway for helium diffusion, and the energetics indicate that the helium generated from tritium decay can accumulate in or near the octahedral sites. Density of states analyses shows the hybridization between palladium d and tritium s orbitals and repulsion between palladium d and helium s orbitals, which can distort the lattice as a result of generating localized stress.


2008 ◽  
Vol 15 (05) ◽  
pp. 567-579 ◽  
Author(s):  
WEI FAN ◽  
XIN-GAO GONG

Based on the Density Functional Theory (DFT) with noncollinear-magnetism formulations, we have calculated the magnetism of single 3d transition-metal atoms and the magnetic anisotropies of supported Ni chains on the Au(110)-(1 × 2) surface. Our results for single absorbed 3d transition-metal atoms show that the surface relaxations enhance the orbital moments of left-end elements (Ti, V) and quenches the orbital moments of right-end elements (Fe, Co, Ni) on the Au(110)-(1 × 2) surface. The magnetic anisotropies of Ni atomic chains on the surface are closely related to orbital quenching. The easy magnetized axes change from the direction parallel to the chains to the direction perpendicular to the Ni chains when they absorb on the surface.


RSC Advances ◽  
2015 ◽  
Vol 5 (103) ◽  
pp. 84381-84388 ◽  
Author(s):  
Zhansheng Lu ◽  
Peng Lv ◽  
Jie Xue ◽  
Huanhuan Wang ◽  
Yizhe Wang ◽  
...  

Single metal atom catalysts exhibit extraordinary activity in a large number of reactions, and some two-dimensional materials (such as graphene and h-BN) are found to be prominent supports to stabilize single metal atoms.


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