Structural trends in hybrid perovskites [Me2NH2]M[HCOO]3 (M = Mn, Fe, Co, Ni, Zn): computational assessment based on Bader charge analysis

CrystEngComm ◽  
2015 ◽  
Vol 17 (2) ◽  
pp. 295-298 ◽  
Author(s):  
Monica Kosa ◽  
Dan Thomas Major
Keyword(s):  
Charge Analysis ◽  
Bader Charge Analysis

Charge partition between the metal and the ligand governs the geometry evolution in hybrid perovskites.

First Principles Investigation of the Stability and the Chemical Behavior of Hydrogen in ThCoH4

2011 ◽  
Vol 66 (3) ◽  
pp. 269-274
Author(s):  
Samir F. Matar
Keyword(s):  
Negative Charge ◽  
Geometry Optimization ◽  
Full Geometry Optimization ◽  
Intermetallic Matrix ◽  
Charge Analysis ◽  
The Stability ◽  
The One ◽  
Site Selective ◽  
Bader Charge Analysis ◽  
Positively Charged

We address the changes in the electronic structure brought by the insertion of hydrogen into ThCo leading to the experimentally observed ThCoH4. Full geometry optimization positions the hydrogen in three sites stabilized in the expanded intermetallic matrix. From a Bader charge analysis, hydrogen is found to be in a narrow iono-covalent (~−0.6) to covalent (~−0.3) bonding which should enable site-selective desorption. The overall chemical picture shows a positively charged Thδ+ with the negative charge redistributed over a complex anion {CoH4}δ− with δ~1.8. Nevertheless this charge transfer remains far from the one in the more ionic hydridocobaltate anion CoH54− in Mg2CoH5, due to the largely electropositive character of Mg.

Experimental and computational investigations of TiIrB: a new ternary boride with Ti1+x Rh2−x+y Ir3−y B3-type structure

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jan P. Scheifers ◽  
Kate A. Gibson ◽  
Boniface P. T. Fokwa
Keyword(s):  
Density Functional ◽  
Ternary Phase ◽  
Structure Type ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
Arc Melting ◽  
Ternary Boride ◽  
Charge Analysis ◽  
First Time ◽  
Bader Charge Analysis

Abstract A new ternary phase, TiIrB, was synthesized by arc-melting of the elements and characterized by powder X-ray diffraction. The compound crystallizes in the orthorhombic Ti1+x Rh2−x+y Ir3−y B3 structure type, space group Pbam (no. 55) with the lattice parameters a = 8.655(2), b = 15.020(2), and c = 3.2271(4) Å. Density Functional Theory (DFT) calculations were carried out to understand the electronic structure, including a Bader charge analysis. The charge distribution of TiIrB in the Ti1+x Rh2−x+y Ir3−y B3-type phase has been evaluated for the first time, and the results indicate that more electron density is transferred to the boron atoms in the zigzag B4 units than to isolated boron atoms.

scholarly journals First-Principle Study of Co-Adsorption Behavior of H2O and O2 on δ-Pu (100) Surface

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1098
Author(s):  
Guoliang Wang ◽  
Zhaoyang Zhao ◽  
Pengfei Zhai ◽  
Xudan Chen ◽  
Yefei Li
Keyword(s):  
Surface Layer ◽  
Energy Analysis ◽  
Co Adsorption ◽  
Adsorption Behavior ◽  
First Principle ◽  
Surface Corrosion ◽  
Preferential Adsorption ◽  
Density Analysis ◽  
Charge Analysis ◽  
Bader Charge Analysis

The surface corrosion of plutonium in air is mainly the result of the interaction with O2 and H2O in air. In this paper, the co-adsorption behavior of O2 and H2O on a δ-Pu (100) surface is studied by the first-principle method. Two different cases of preferential adsorption of H2O and O2 are considered, respectively. Bader charge analysis and adsorption energy analysis are carried out on all stable adsorption configurations, and the most stable adsorption configurations are found under the two conditions. The results of differential charge density analysis, the density of states analysis and Crystal Orbital Hamilton Populations (COHP) analysis show that the two molecules can promote each other’s adsorption behavior, which leads to the strength and stability of co-adsorption being far greater than that of single adsorption. In the co-adsorption configuration, O atoms preferentially interact with Pu atoms in the surface layer, and the essence is that the 2s and 2p orbitals of O overlap and hybridize with the 6p and 6d orbitals of Pu. H atoms mainly form O–H bonds with O atoms and hardly interact with Pu atoms on the surface layer.

scholarly journals Catalytic Effect of Hydrogen Bond on Oxhydryl Dehydrogenation in Methanol Steam Reforming on Ni(111)

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1531
Author(s):  
Changming Ke ◽  
Zijing Lin
Keyword(s):  
Hydrogen Bond ◽  
Steam Reforming ◽  
Methanol Steam Reforming ◽  
Elastic Band ◽  
Charge Analysis ◽  
Band Method ◽  
Dehydrogenation Reactions ◽  
Key Steps ◽  
Bader Charge Analysis

Dehydrogenation of H3COH and H2O are key steps of methanol steam reforming on transition metal surfaces. Oxhydryl dehydrogenation reactions of HxCOH (x = 0–3) and OH on Ni (111) were investigated by DFT calculations with the OptB88-vdW functional. The transition states were searched by the climbing image nudged elastic band method and the dimer method. The activation energies for the dehydrogenation of individual HxCOH* are 68 to 91 kJ/mol, and reduced to 12–17 kJ/mol by neighboring OH*. Bader charge analysis showed the catalysis role of OH* can be attributed to the effect of hydrogen bond (H-bond) in maintaining the charge of oxhydryl H in the reaction path. The mechanism of H-bond catalysis was further demonstrated by the study of OH* and N* assisted dehydrogenation of OH*. Due to the universality of H-bond, the H-bond catalysis shown here, is of broad implication for studies of reaction kinetics.

scholarly journals Novel Unexpected Reconstructions of (100) and (111) Surfaces of NaCl: Theoretical Prediction

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Alexander G. Kvashnin ◽  
Dmitry G. Kvashnin ◽  
Artem R. Oganov
Keyword(s):  
Crystal Morphology ◽  
Chemical Potential ◽  
Rehbinder Effect ◽  
High Chemical ◽  
Chemical Potentials ◽  
Wide Range ◽  
Surface Phases ◽  
Charge Analysis ◽  
Bader Charge Analysis ◽  
Very High

Abstract We have predicted stable reconstructions of the (100) and (111) surfaces of NaCl using the global optimization algorithm USPEX. Several new reconstructions, together with the previously reported ones, are found. For the cleaved bare (100) surface, pure Na and pure Cl are the only stable surface phases. Our study of the (111) surface shows that a newly predicted Na3Cl-(1 × 1) reconstruction is thermodynamically stable in a wide range of chlorine chemical potentials. It has a sawtooth-like profile where each facet reproduces the (100) surface of rock-salt NaCl, hinting on the preferred growth of the (100) surface. We used Bader charge analysis to explain the preferable formation of this sawtooth-like Na3Cl-(1 × 1) reconstruction of the (111) surface of NaCl. We find that at a very high chemical potential of Na, the polar (and normally absent) (111) surface becomes part of the equilibrium crystal morphology. At both very high and very low chemical potentials of Cl, we predict a large decrease of surface energy and fracture toughness (the Rehbinder effect).

scholarly journals A new family of copper-based MXenes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. Ponce-Pérez ◽  
S. J. Gutierrez-Ojeda ◽  
J. Guerrero-Sánchez ◽  
María G. Moreno-Armenta
Keyword(s):  
Biomedical Applications ◽  
Ionic Character ◽  
Experimental Realization ◽  
Oh Groups ◽  
New Family ◽  
Phonon Spectra ◽  
Charge Analysis ◽  
Bader Charge Analysis ◽  
Magnetic Nature ◽  
Positively Charged

AbstractIn this work, we demonstrate, through first-principles calculations, the existence of a new family of copper-based MXenes. These add up new structures to the previously reported universe and span the interest of such 2D materials for applications in heterogeneous catalysis, ion-based batteries, sensors, biomedical applications, and so on. First, we propose the MXene-like structures: Cu2N, Cu2C, and Cu2O. Phonon spectra calculations confirmed their dynamical stability by showing just positive frequencies all through the 2D Brillouin zone. The new MXenes family displays metallic characteristics, mainly induced by the Cu-3d orbitals. Bader charge analysis and charge density differences depict bonds with ionic character in which Cu is positively charged, and the non-metal atom gets an anionic character. Also, we investigate the functionalization of the proposed structures with Cl, F, O, and OH groups. Results show that the H3 site is the most favorable for functionalization. In all cases, the non-magnetic nature and metallic properties of the pristine MXenes remain. Our results lay the foundations for the experimental realization of a new MXenes family.

The Effect of the Size and Electronic Factor on Occupation and Magnetic Property of Co Addition in L10 FePt Alloy

2013 ◽  
Vol 749 ◽  
pp. 461-465
Author(s):  
Xiao Lin Shu ◽  
Yong Fei Jia ◽  
Zi Yu Chen
Keyword(s):  
Magnetic Property ◽  
Contour Plot ◽  
Size Factor ◽  
Electronic Factor ◽  
Fept Alloy ◽  
Charge Density Difference ◽  
Charge Analysis ◽  
Co Addition ◽  
Sublattice Site ◽  
Bader Charge Analysis

The size and the electronic factor are used to analyze the occupation of doped Co atom in L10 FePt alloy as well as its influence on crystal structure and magnetic property. The Co atom located in Fe sublattice site is determined by the variance of the calculated structure and the doping energy results investigated by the first-principles calculations. The charge-density difference contour plot and Bader charge analysis can quantitatively distinguish the effects of the size and the electronic factor on physical properties of the doping alloy. The effect of the electronic factor on the doping energy is more dominant than that of the size factor. The size factor almost has no effect on saturation magnetization.

scholarly journals Absorption of Isopropanol on Surface of Defect Silicene

2020 ◽  
Vol 36 (3) ◽  
Author(s):  
Vo Van On ◽  
Pham Trong Lam ◽  
Dinh Van An
Keyword(s):  
Charge Transfer ◽  
Density Functional ◽  
Lower Layer ◽  
Density Functional Theory Method ◽  
Metallic Behavior ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Gap Characteristics ◽  
Charge Analysis ◽  
Bader Charge Analysis

  In this work, we investigate the defect structure of Silicene with a vancacy and the adsorption mechanism of isopropanol on the surface of defected Silicene by employing the Density Functional Theory method. The adsorption profile was determined based on van der Waals functional optPBE-vdW and the charge transfer between isopropanol and silicene this system was also calculated by Bader charge analysis method. In the defected Silicene, Si vacancy preferably forms on the lower layer of the bulking structure. As a Si vacancy is introduced, Silicene exhibits a metallic behavior with zero bandgap. Due to the losing electron of defected Silicene, isopropanol is adsorbed on the surface with the most favourable adsorption configuration in which oxygen atom towards the surface of Silicene. Isopropanol adsorption opens a tunnelling gap of defected Silicence, resulting in the mili-gap characteristics of the adsorbed Silicene system. The adsorption profile of this volatile organic compound on defected Silicene implies the physics adsorption characteristics. The adsorption energy for isopropanol was found to be -0.40 eV. In addition, the charge transfer of 0.24 electron was obtained

scholarly journals Toxic Gases on β12 Borophene: the Selective Adsorption

2020 ◽  
Vol 36 (2) ◽  
Author(s):  
Ta Thi Luong ◽  
Pham Trong Lam ◽  
Dinh Van An
Keyword(s):  
Selective Adsorption ◽  
Electronic Devices ◽  
First Principle ◽  
First Principle Calculations ◽  
Toxic Gases ◽  
Charge Analysis ◽  
Gas Molecules ◽  
Selective Adsorbent ◽  
And Diffusion ◽  
Bader Charge Analysis

Borophene, a new member of the 2D material family, was proven theoretically and empirically in many recent studies that it has a unique structure and promising properties applied in batteries and electronic devices. In this work, the adsorbability of β12 – borophene towards some main poisonous gases was investigated. Herein, first-principle calculations were employed to obtain the adsorption configurations, adsorption energy of CO, NO, CO2, NH3, and NO2 on b12 – borophene by using three van der Waals correlation functionals: revPBE-vdW, optPBE-vdW, and vdW-DF2. Also, the most stable configurations and diffusion possibilities of the gas molecules on the surface of b12 – borophene were determined visually by using Computational DFT-based Nanoscope. The nature of bonding and interaction between gas molecules and b12 – borophene were disclosed by using the density of states analysis and Bader charge analysis. Remarkably, borophene exhibits as a highly selective adsorbent when having great interactions with NOx gases outweigh the others.

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