scholarly journals Li and Na Adsorption on Graphene and Graphene Oxide Examined by Density Functional Theory, Quantum Theory of Atoms in Molecules, and Electron Localization Function

Molecules ◽  
2019 ◽  
Vol 24 (4) ◽  
pp. 754 ◽  
Author(s):  
Nicholas Dimakis ◽  
Isaiah Salas ◽  
Luis Gonzalez ◽  
Om Vadodaria ◽  
Korinna Ruiz ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Graphene Oxide ◽  
Quantum Theory ◽  
Density Functional ◽  
Electron Localization Function ◽  
Electron Localization ◽  
Functional Theory ◽  
Localization Function ◽  
Metal Metal ◽  
Metal Bonds

Adsorption of Li and Na on pristine and defective graphene and graphene oxide (GO) is studied using density functional theory (DFT) structural and electronic calculations, quantum theory of atoms in molecules (QTAIM), and electron localization function (ELF) analyses. DFT calculations show that Li and Na adsorptions on pristine graphene are not stable at all metal coverages examined here. However, the presence of defects on graphene support stabilizes both Li and Na adsorptions. Increased Li and Na coverages cause metal nucleation and weaken adsorption. Defective graphene is associated with the presence of band gaps and, thus, Li and Na adsorptions can be used to tune these gaps. Electronic calculations show that Li– and Na–graphene interactions are Coulombic: as Li and Na coverages increase, the metal valences partially hybridize with the graphene bands and weaken metal–graphene support interactions. However, for Li adsorption on single vacancy graphene, QTAIM, ELF, and overlap populations calculations show that the Li-C bond has some covalent character. The Li and Na adsorptions on GO are significantly stronger than on graphene and strengthen upon increased coverages. This is due to Li and Na forming bonds with both carbon and oxygen GO atoms. QTAIM and ELF are used to analyze the metal–C and metal–metal bonds (when metal nucleation is present). The Li and Na clusters may contain both covalent and metallic intra metal–metal bonds: This effect is related to the adsorption support selection. ELF bifurcation diagrams show individual metal–C and metal–metal interactions, as Li and Na are adsorbed on graphene and GO, at the metal coverages examined here.

Predicting bond dissociation energy and bond length for bimetallic diatomic molecules: a challenge for electronic structure theory

2017 ◽  
Vol 19 (8) ◽  
pp. 5839-5854 ◽  
Author(s):  
Junwei Lucas Bao ◽  
Xin Zhang ◽  
Xuefei Xu ◽  
Donald G. Truhlar
Keyword(s):  
Density Functional Theory ◽  
Active Sites ◽  
Density Functional ◽  
Electronic Structure Theory ◽  
Structure Theory ◽  
Strongly Correlated ◽  
Functional Theory ◽  
Metal Metal ◽  
Catalytically Active ◽  
Metal Bonds

We test the accuracy of Kohn–Sham density functional theory for strongly correlated metal–metal bonds that occur in catalytically active sites and intermediates and examine the orbitals and configurations involved to analyze the results.

scholarly journals N-t-Butyl-α-aryl Nitrones as Potent Spin Traps: DFT Analysis of Electron Localization Function Topology, Local Selectivity, Reactivity and Solvent Effects

2020 ◽  
Vol 32 (5) ◽  
pp. 1191-1196
Author(s):  
Nivedita Acharjee ◽  
Sourav Mondal
Keyword(s):  
Density Functional ◽  
Population Analysis ◽  
Topological Analysis ◽  
Electron Localization Function ◽  
Electron Localization ◽  
Functional Theory ◽  
Biologically Relevant ◽  
Localization Function ◽  
Chemical Potentials ◽  
Electronic Chemical

Density functional theory studies were performed to analyze the reactivity and selectivity of radical capture by N-t-butyl-α-aryl nitrones. Biologically relevant three important radicals viz. hydroxyl, methyl and hydroperoxyl were selected for the study. Topological analysis of the electron localization function (ELF) allows to classify these nitrones as zwitter-ionic type three atom components (TAC). Effects of electron withdrawing and electron donating C-aryl substituents on the electronic chemical potentials, global hardness, electrophilic and nucleophilic indices of nitrones were observed. Radical attack at the carbon atom was predicted by Merz-Kollman algorithm, which is in agreement with the experiments unlike the natural population analysis. Hydroxyl adducts were predicted to be more stable than methyl and hydroperoxyl adducts. cis-Adducts were more stable than the trans-, with the highest differences in stability noted for the methyl adducts. Relative energies of adducts was lowered in non-polar solvents and thus increase in stability was observed along the series from water to heptane.

scholarly journals Atoms in Highly Symmetric Environments: H in Rhodium and Cobalt Cages, H in an Octahedral Hole in MgO, and Metal Atoms Ca-Zn in C20 Fullerenes

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1281
Author(s):  
Zikri Altun ◽  
Erdi Ata Bleda ◽  
Carl Trindle
Keyword(s):  
Density Functional Theory ◽  
Quantum Theory ◽  
Coordination Number ◽  
Electronic Structures ◽  
Density Functional ◽  
Functional Theory ◽  
Metal Atoms ◽  
Tetragonal Pyramidal ◽  
Non Covalent Interactions ◽  
Covalent Interactions

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.

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