Stability, Electronic Properties, and Structural Isomerism in Small Copper Clusters

2012 ◽  
Vol 1479 ◽  
pp. 15-20
Author(s):  
Juan M. Montejano-Carrizales ◽  
Faustino Aguilera-Granja ◽  
Ricardo A. Guirado-López
Keyword(s):  
Electronic Properties ◽  
Density Functional ◽  
Three Dimensional ◽  
Density Functional Theory Calculations ◽  
Energy Barriers ◽  
Elastic Band ◽  
Experimental Conditions ◽  
Atomic Displacements ◽  
Structural Isomerism ◽  
The Stability

ABSTRACTWe present extensive pseudopotential density functional theory calculations dedicated to analyze the stability, electronic properties, and structural isomerism in Cu6 clusters. We consider structures of different symmetries and charge states. Our total energy calculations reveal a strong competition between two- and three-dimensional atomic arrays, the later being mostly energetically preferred for the anionic structures. The bond lengths and electronic spectra strongly depend on the local atomic environment, a result that is expected to strongly influence the catalytic activity of our clusters. Using the nudged elastic band method we analyze the interconversion processes between different Cu6 isomers. Complex atomic relaxations are obtained when we study the transition between different cluster structures; however relatively small energy barriers of approximately 0.3 eV accompany the atomic displacements. Interestingly, we obtain that by considering positively charged Cu6+ systems we reduce further the energy barriers opposing the interconversion process. The previous results could imply that, under a range of experimental conditions, it should be possible to observe different Cu6cluster structures in varying proportions.

DFT STUDIES ON THE STABILITY OF THE TRANS AND CIS ISOMERS IN THE SQUARE PLANAR PALLADIUM(II) COMPLEXES Pd(I)(PPh3)(η3-XCHC(Ph)CHR) (X = CMe3, CO2Me, P(O)(OMe)2, AND SO2H; R = H, Me)

2008 ◽  
Vol 07 (04) ◽  
pp. 505-515
Author(s):  
LIQIN XUE ◽  
GUOCHEN JIA ◽  
ZHENYANG LIN
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Relative Stability ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Dft Studies ◽  
Functional Theory ◽  
Square Planar ◽  
The Stability ◽  
Cis Isomer

The relative stability of the trans and cis isomers in the square planar palladium(II) complexes Pd ( I )( PPh 3)(η3- XCHC ( Ph ) CHR ) ( X = H , Me , CMe 3, CO 2 Me , P ( O )( OMe )2, and SO 2 H ; R = H , Me ) was investigated with the aid of the B3LYP density functional theory calculations. We examined how the substituents X, with different electronic properties, of the η3-allyl ligands affect the relative stability of the trans and cis isomers. Through the investigation, we were able to explain the trans/cis relative stability derived from the experimentally measured trans/cis isomer ratios in the palladium(II) complexes.

A Density Functional Theory Study on the Structures and Electronic Properties of XAln (X = Br, I; n = 3–15) Clusters

2019 ◽  
Vol 74 (2) ◽  
pp. 121-129 ◽  
Author(s):  
Ming Hui ◽  
Qing-Huai Zhao ◽  
Zhi-Peng Wang ◽  
Shuai Zhang ◽  
Gen-Quan Li
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Density Functional ◽  
Energy Gap ◽  
Three Dimensional ◽  
Density Functional Theory Calculations ◽  
Chemical Hardness ◽  
Geometrical Structures ◽  
Functional Theory ◽  
The Density Functional Theory

AbstractThe effects of halogen element X (X = Br, I) doping on the geometrical structures and electronic properties of neutral aluminium clusters are systematically studied by utilising the density functional theory calculations. The structures of X-doped clusters show the three-dimensional forms with increasing atomic number except for n = 3 and X (X = Br, I) atom prefer to occupy the surface site of the host Aln clusters. BrAl7 and IAl7 clusters are the most stable geometries. The HOMO-LUMO energy gap and chemical hardness show an odd–even alternative phenomenon. The charges always transfer from the Al atoms to the X (X = Br, I) atom. Finally, the dipole and polarisability are discussed.

scholarly journals Structure and stability of two dimensional phosphorene with O or NH functionalization

RSC Advances ◽  
2014 ◽  
Vol 4 (89) ◽  
pp. 48017-48021 ◽  
Author(s):  
Jun Dai ◽  
Xiao Cheng Zeng
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Two Dimensional ◽  
Functional Theory ◽  
Structure And Stability ◽  
Single Side ◽  
The Stability

We investigate the stability and electronic properties of oxy- (O) or imine- (NH) functionalized monolayer phosphorene with either single-side or double-side functionalization based on density-functional theory calculations.

scholarly journals Defect Processes in Halogen Doped SnO2

2021 ◽  
Vol 11 (2) ◽  
pp. 551
Author(s):  
Petros-Panagis Filippatos ◽  
Nikolaos Kelaidis ◽  
Maria Vasilopoulou ◽  
Dimitris Davazoglou ◽  
Alexander Chroneos
Keyword(s):  
Electronic Properties ◽  
Tin Oxide ◽  
Density Functional ◽  
Structural Changes ◽  
High Dielectric Constant ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Optical And Electronic Properties ◽  
High Dielectric ◽  
Gap States

In the present study, we performed density functional theory calculations (DFT) to investigate structural changes and their impact on the electronic properties in halogen (F, Cl, Br, and I) doped tin oxide (SnO2). We performed calculations for atoms intercalated either at interstitial or substitutional positions and then calculated the electronic structure and the optical properties of the doped SnO2. In all cases, a reduction in the bandgap value was evident, while gap states were also formed. Furthermore, when we insert these dopants in interstitial and substitutional positions, they all constitute a single acceptor and donor, respectively. This can also be seen in the density of states through the formation of gap states just above the valence band or below the conduction band, respectively. These gap states may contribute to significant changes in the optical and electronic properties of SnO2, thus affecting the metal oxide’s suitability for photovoltaics and photocatalytic devices. In particular, we found that iodine (I) doping of SnO2 induces a high dielectric constant while also reducing the oxide’s bandgap, making it more efficient for light-harvesting applications.

scholarly journals Oxygen Vacancy Induced Magnetism in Anti-Perovskite Topological Dirac Semimetal Ba3SnO

2021 ◽  
Author(s):  
Javaria Batool ◽  
Syed Muhammad Alay-e-Abbas ◽  
Gustav Johansson ◽  
Waqas Zulfiqar ◽  
Muhammad Arsam Danish ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Oxygen Vacancy ◽  
Electronic Properties ◽  
Thermodynamic Stability ◽  
First Principles ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Vacancy Defect ◽  
Functional Theory ◽  
Dirac Semimetal

The thermodynamic, structural, magnetic and electronic properties of pristine and intrinsic vacancy defect containing topological Dirac semimetal Ba3SnO are studied using first-principles density functional theory calculations. The thermodynamic stability of...

scholarly journals Breathing distortions in the metallic, antiferromagnetic phase of LaNiO$_3$

2018 ◽  
Vol 5 (3) ◽  
Author(s):  
Alaska Subedi
Keyword(s):  
Density Functional ◽  
Recent Observation ◽  
Quantum Critical Point ◽  
Three Dimensional ◽  
Density Functional Theory Calculations ◽  
Antiferromagnetic Phase ◽  
Functional Theory ◽  
Antiferromagnetic Ordering ◽  
Spin Polarized ◽  
Structural Fluctuations

I study the structural and magnetic instabilities in LaNiO_33 using density functional theory calculations. From the non-spin-polarized structural relaxations, I find that several structures with different Glazer tilts lie close in energy. The PnmaPnma structure is marginally favored compared to the R\overline{3}cR3¯c structure in my calculations, suggesting the presence of finite-temperature structural fluctuations and a possible proximity to a structural quantum critical point. In the spin-polarized relaxations, both structures exhibit the \uparrow\!\!0\!\!\downarrow\!\!0↑0↓0 antiferromagnetic ordering with a rock-salt arrangement of the octahedral breathing distortions. The energy gain due to the breathing distortions is larger than that due to the antiferromagnetic ordering. These phases are semimetallic with small three-dimensional Fermi pockets, which is largely consistent with the recent observation of the coexistence of antiferromagnetism and metallicity in LaNiO_33 single crystals by Guo et al. [Nat. Commun. 9, 43 (2018)].

scholarly journals An Experimental and Theoretical Study on the Effect of Silver Nanoparticles Concentration on the Structural, Morphological, Optical, and Electronic Properties of TiO2 Nanocrystals

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1488
Author(s):  
Faheem Ahmed ◽  
Mohammed Benali Kanoun ◽  
Chawki Awada ◽  
Christian Jonin ◽  
Pierre-Francois Brevet
Keyword(s):  
Electronic Properties ◽  
Density Functional ◽  
Anatase Phase ◽  
Density Functional Theory Calculations ◽  
Tio2 Nanocrystals ◽  
Uniform Size ◽  
Chemical Route ◽  
Structural And Electronic Properties ◽  
Nanoparticles Concentration ◽  
Gap States

In this work, pure and silver (Ag)-loaded TiO2 nanocrystals (NCs) with various concentrations of Ag were prepared by soft chemical route and the effect of Ag nanoparticles (NPs) on the functional properties of TiO2 was studied. X-ray diffraction (XRD) and Raman studies confirmed that the synthesized product had single-phase nature and high crystalline quality. The crystallite size was decreased from 18.3 nm to 13.9 nm with the increasing in concentration of Ag in TiO2 NCs. FESEM micrographs showed that the pure and AgNPs-loaded TiO2 have spherical morphology and uniform size distribution with the size ranging from 20 to 10 nm. Raman spectroscopy performed on pure and AgNPs-loaded TiO2 confirms the presence of anatase phase and AgNPs. Optical properties show the characteristics peaks of TiO2 and the shifting of the peaks position was observed by changing the concentration of Ag. The tuning of bandgap was found to be observed with the increase in Ag, which could be ascribed to the synergistic effect between silver and TiO2 NCs. Density functional theory calculations are carried out for different Ag series of doped TiO2 lattices to simulate the structural and electronic properties. The analysis of the electronic structures show that Ag loading induces new localized gap states around the Fermi level. Moreover, the introduction of dopant states in the gap region owing to Ag doping can be convenient to shift the absorption edge of pristine TiO2 through visible light.

scholarly journals Mechanochemical Synthesis of a Mercury(II) Metal-Organic Framework Reveals a Two-Dimensional Polymorph Stabilized by Weak Interactions

2019 ◽  
Author(s):  
Isaiah R. Speight ◽  
Igor Huskić ◽  
Mihails Arhangelskis ◽  
Hatem M. Titi ◽  
Robin Stein ◽  
...  
Keyword(s):  
Density Functional ◽  
Weak Interactions ◽  
Metal Organic Framework ◽  
Three Dimensional ◽  
Density Functional Theory Calculations ◽  
Dimensional Structure ◽  
Reaction Monitoring ◽  
Two Dimensional ◽  
Functional Theory ◽  
Metal Organic

Solid-state mechanochemistry revealed a novel polymorph of the mercury(II) imidazolate framework, based on square-grid (sql) topology layers. Reaction monitoring and periodic density functional theory calculations show that the sql-structure is of higher stability than the previously reported three-dimensional structure, with the unexpected stabilization of a lower dimensionality structure explained by contributions of weak interactions, which include short C-H···Hg contacts.

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