Overlap Population Research Articles

Evaluation of covalency of ions in lead-free perovskite-type dielectric oxides

Electronic states of ions in lead-free perovskite-type dielectric oxides have been investigated with a first-principle cluster calculation. For this calculation a double-perovskite cluster model based upon the simple cubic ABO3 was used; A and B are both the cations, and O is the oxygen anion. Systematic variations of ionic species for A and B, and lengths of the model cube edge were given to the model. Results of charge transfers of the ions show that their magnitudes depend on the edge length; the lager length leads to the higher transfer magnitude. This tendency implies spatial tolerance of the ions to the clusters, and are expected to correlate with electric polarizability and dipole reversibility of this kind of oxides. The density of states and the overlap population indicate that the higher cation valence causes the higher covalency of the anions. Considering all results together provides us an idea to obtain lead-free high-performance ferroelectrics, as high as the lead-based solid solutions.

Photoelectric properties of Mn-doped LiMgP new diluted magnetic semiconductor

We optimized the geometry structures of Li1± y (Mg1− x Mn x )P for ( x =0.125; y =0, 0.125) by adopting the first-principles calculation of plane wave ultra-soft pseudo-potential technology based upon the density function theory (DFT). Then we calculated the electronic structures, formation energies, electric density difference and optical properties. The results reveal that spin polarization impurity bands were produced in Mn doped system. The properties of system and the orbits of participate in hybridization could be changed by dominating the amount of Li. The Mn doped system still revealed semiconductor properties, and the width of impurity band is 0.461 eV, and the magnetic moment is 4.98 μ в. The Li overdose system revealed metallicity, and the width of impurity bands increased to 0.890 eV, and the magnetic moment decreased to 4.10 μ в. Meanwhile the total energies and the formation energies reduced, the conductive capability increased. The Li deficient system revealed half metallicity, and the half-metallic band gap is 0.478 eV, and the magnetic moment is 4.02 μ в. Most of the charge overlap populations of LiMgP system are positive. It means all the chemical bonds of LiMgP are covalent bonds. Magnetism element Mn doped into the system creates Mn-P covalent bonds that are stronger than Mg-P bonds. In the Mn doped system, the quantity of share electron increased and the deviation of share electron decreased. The charge overlap population of Li-P bond is −0.02 which reveals ionic bonds. In the Li overdose system, the charge overlap population of Mn-P bonds reach the minimum value of 0.52. The density of states of Mn3 d and P3 p at the Fermi level is larger than that of single doped Mn, but at the same time, the interaction of the Mn-P bonds is weakened due to the participation of Li2 s in orbital hybridization. Formation energy and total energy become lower. And in the Li deficient system, the charge overlap population of Mn-P bonds reached the maximum value of 0.69, and the bonds lengths reached the minimum value. The electron cloud of Mn atoms and P atoms is the densest, and the deviation of the share electron is the weakest. The results reveal that p-d hybridization happened in Mn3 d and P3 p , and the hybridization was the strongest. The deficiency of the electron cloud of P atoms of charge density difference was caused by the deficiency of Li atoms. Analyzing images of optical properties can find that the imaginary part of dielectric function and the optical spectroscopy appeared a new peak at low energy region in Mn doped system. And the complex refractive index functions have a significant change at the same time. It means the system has an augment optical absorption range, and energy loss get lower.

First-principles investigations of the electronic and magnetic structures and the bonding properties of uranium nitride fluoride (UNF)

AbstractBased on geometry optimization and magnetic structure investigations within density functional theory, a unique uranium nitride fluoride, isoelectronic with UO2, is shown to present peculiar differentiated physical properties. These specificities versus the oxide are related to the mixed anionic substructure and the layered-like tetragonal structure characterized by covalent-like [U2N2]2+motifs interlayered by ionic-like [F2]2−ones and illustrated herein with electron localization function projections. Particularly, the ionocovalent chemical picture shows, based on overlap population analyses, stronger U–N bonding versus U–F andd(U–N)<d(U–F) distances. Further generalized gradient approximation+U calculations provide the ground state magnetic structure as insulating antiferromagnet with ±2 μBmagnetization per magnetic sub-cell and ~2 eV band gap.

Ab initio study of ionic nature of 0.75AgI:0.25AgCl

Ab initio calculations based on density functional theory are performed for zinc-blende structured new host 0.75AgI:0.25AgCl. Eight configurations are simulated for different positions of Cl atoms, and they are divided into three sets of configurations. Similar calculations are also performed for zinc blende β-AgI. Bond lengths are changed and p-d hybridization is observed in all configurations. Ionic nature of atomic bonds is analyzed by the ionicity factor. The charge density analysis also exhibits the ionic and least covalent nature of bonds of AgI and AgCl atoms. The structural parameters are calculated to observe the bulk modulus. Crystal orbital overlap population analysis explains the inter-atomic bond strength which explains the bond breaking energy and activation energy of all configurations.

Aluminum–phosphorus triple bonds: Do substituents make Al[tbnd6]P synthetically accessible?

The effect of substitution on the potential energy surfaces of triple-bonded RAlPR (R=F, OH, H, CH3, SiH3, SiMe(SitBu3)2, SiiPrDis2, Tbt (C6H2-2,4,6-{CH(SiMe3)2}3), and Ar∗ (C6H3-2,6-(C6H2-2,4,6-i-Pr3)2)) compounds was investigated by using the theoretical methods (i.e., M06-2X/Def2-TZVP, B3PW91/Def2-TZVP, B3LYP/LANL2DZ+dp, and CCSD(T)). The theoretical examinations reveal that all of the triple-bonded RAlPR species prefer to adopt a bent form with a roughly perpendicular bond angle (∠Al–P–R). In addition, the theoretical evidence demonstrates that only the bulkier substituents can efficiently stabilize the central AlP triple bond. Moreover, the theoretical analyses (the natural bond orbital, the natural resonance theory, and the charge decomposition analysis) indicate that the bonding characters of the triply bonded RAlPR molecules should be described as R′Al▪PR′. That is to say, the AlP triple bond contains one conventional σ bond, one conventional π bond, and one donor-acceptor π bond. Nevertheless, the theoretical conclusions based on the poor overlap populations between Al and P elements suggest the AlP triple bond in such an acetylene analogues (RAlPR) is likely to be very weak.

First principle studies on electronic structure and charge density of potato starch

The electronic and chemical bonding properties of biomaterial potato starch within the density functional theory are presented in this paper, with the aim to be used in electrochemical devices and biomedical applications. In the density of states and projected density of states analysis, the energy difference between the highest occupied molecular orbital and lowest unoccupied molecular orbital is reduced by 2.9 eV, which exhibits the semi-conducting behaviour of modified potato starch in the presence of NaI salt. Calculated charge density predicts the bonding properties and crystal orbital overlap population analysis exhibits the increase of amorphous nature and ionic conductivity due to sodium ion concentration. In this theoretical study, different behaviours of modified potato starch are clearly seen in the presence of NaI salt.

DFT study of β-d-glucose adsorption on single-walled carbon nanotubes decorated with platinum. A bonding analysis

Adsorption of β-d-glucose onto Pt decorated carbon nanotubes (CNTs) was studied using density functional theory (DFT) methods including van der Waals (vdW) forces. Several adsorption geometries were analyzed evaluating the aptitude of different atoms fromβ-d-glucose molecule to be bonded with a Pt atom previously supported. The influence of vdW interactions in structure stabilization was also studied using overlap population (OP) and bonding order (BO) analysis. The results show strong short-range bonds between the O atoms from β-d-glucose and Pt decoration. The long-range interactions, mainly from O and H atoms from the adsorbate, demonstrate a significant contribution for stabilization of some geometric configurations. In effect, adsorption geometries where glucose interacts though the O atom of the ring or OH groups are favored by vdW forces, becoming the most stable systems. On the other hand, the geometry with the strongest OPt bond but a very small contribution from vdW interactions results less stable. DOS analysis shows the stabilization of β-d-glucose after adsorption and a strong chemical interaction with Pt/CNT.

In-situ studies on the micro-structure evolution of A2W2O7 (A = Li, Na, K) during melting by high temperature Raman spectroscopy and density functional theory

In-situ high temperature Raman spectroscopic (HTRS) technique in combination with density functional theory (DFT) analysis has been adopted to investigate the micro-structure of solid and molten A2W2O7 (A=Li, Na, K). The [WO6] octahedra were found to be connected to each other by corner and edge sharing in the crystalline Li2W2O7 and K2W2O7 compounds. In the crystal lattice of Na2W2O7, on the other hand, the [WO4] tetrahedra and [WO6] octahedra were found to coexist and paired by corner sharing. Although the structural diversity has clearly led to distinct Raman spectra of the crystalline A2W2O7 compounds, the spectra of their melts tended to be analogous, showing the typical vibration modes of (W2O7)2− dimer. A mechanism was then proposed to explain the structure evolution occurring during the melting process of A2W2O7. The effect of A+ cation on the Raman bands of (W2O7)2− dimer in molten A2W2O7 has also been investigated. Both the wavenumber and full width at half-height (FWHH) of the characteristic band assigned to the symmetrical stretching vibration mode of WOnb (non-bridging oxygen) in (W2O7)2− were found to decrease in the sequence of Li+, Na+ and K+, indicating the cation effect on the mean bond length and its distribution range of WOnb. In addition, the relative intensity of this band was also influenced by the cation and it was increased in the order of Li2W2O7, Na2W2O7 and K2W2O7, which has been explained by the charge transfer process and confirmed by Mulliken overlap population analysis.

Cu6 (NGuaS)6 ]2+ and its oxidized and reduced derivatives: Confining electrons on a torus.

The hexanuclear thioguanidine mixed-valent copper complex cation [Cu6 (NGuaS)6 ]+2 (NGuaS = o-SC6 H4 NC(NMe2 )2 ) and its oxidized/reduced states are theoretically analyzed by means of density functional theory (DFT) (TPSSh + D3BJ/def2-TZV (p)). A detailed bonding analysis using overlap populations is performed. We find that a delocalized Cu-based ring orbital serves as an acceptor for donated S p electrons. The formed fully delocalized orbitals give rise to a confined electron cloud within the Cu6 S6 cage which becomes larger on reduction. The resulting strong electrostatic repulsion might prevent the fully reduced state. Experimental UV/Vis spectra are explained using time-dependent density functional theory (TD-DFT) and analyzed with a natural transition orbital analysis. The spectra are dominated by MLCTs within the Cu6 S6 core over a wide range but LMCTs are also found. The experimental redshift of the reduced low energy absorption band can be explained by the clustering of the frontier orbitals. © 2017 Wiley Periodicals, Inc.

Copper(I) Complexes with Thiourea Derivatives as Ligands: Revealing Secrets of Their Bonding Scheme

We have synthesized and characterized five copper(I) complexes with unsymmetrically substituted thiourea ligands. These include two coordination polymers, [Cu(StuNH)Br]nand [Cu(Stu(Py)NH)Br]n, two dinuclear complexes, [Cu2(StuNH)4Br2] and [Cu2(Stu(Py)NH)2Br2(MeCN)2], and one hexanuclear complex, [Cu6(StuN)6]. The Cu atoms of the coordination polymers are connected through alternating thione and bromide bridges and the dimeric structures through thione bridges. The thione‐bridged structures show similarities with the biologically highly relevant CuAcenter in its fully reduced oxidation state. Three of the complexes were further investigated by using DFT, including a full orbital analysis utilizing fragment orbitals (FOs) and overlap populations (OPs). The bonding motifs of the dinuclear complexes are similar to that of the CuAcomplex, whereas the analysis of the hexanuclear species showed the influence of the ligands on the core and hence on its electronic structure. Moreover, a comparative analysis of related dinuclear and hexanuclear copper–sulfur systems is presented.

Structural inheritance and difference between Ti2AlC, Ti3AlC2 and Ti5Al2C3 under pressure from first principles

The structural inheritance and difference between Ti2AlC, Ti3AlC2 and Ti5Al2C3 under pressure from first principles are studied. The results indicate that the lattice parameter a are almost the same within Ti2AlC, Ti3AlC2 and Ti5Al2C3, and the value of c in Ti5Al2C3 is the sum of Ti2AlC and Ti3AlC2 which is revealed by the covalently bonded chain in the electron density difference: Al–Ti–C–Ti–Al for Ti2AlC, Al–Ti2–C–Ti1–C–Ti2–Al for Ti3AlC2 and Al–Ti3–C2–Ti3–Al–Ti2–C1–Ti1–C1–Ti2–Al for Ti5Al2C3. The calculated axial compressibilities, volumetric shrinkage, elastic constant [Formula: see text], [Formula: see text] ratio, bulk modulus, shear modulus, and Young’s modulus of Ti5Al2C3 are within the range of the end members (Ti2AlC and Ti3AlC2) in a wide pressure range of 0–100 GPa. Only Ti2AlC is isotropic crystal at about 50 GPa within the Ti–Al–C compounds. All of the Ti 3d density of states curves of the three compounds move from lower energy to higher energy level with pressure increasing. The similarities of respective bond length, bond overlap population (Ti–C, Ti–Al and Ti–Ti), atom Mulliken charges under pressure as well as the electron density difference for the three compounds are discovered. Among the Ti–Al–C ternary compounds, Ti–Ti bond behaves least compressibility, whereas the Ti–Al bond is softer than that of Ti–C bonds, which can also been confirmed by the density of states and electron density difference. Bond overlap populations of Ti–Ti, Ti–C and Ti–Al indicate that the ionicity interaction becomes more and more stronger in the three structures as the pressure increasing. Mulliken charges of Ti1, Ti2, Ti3, C and Al are 0.65, 0.42, 0.39, −0.73, −0.04 at 0 GPa, respectively, which are consistent with the Pauling scale.

Investigations on the frontier orbitals of FeFn (n = 1–6) superhalogen complexes and prediction of novel salt series Li-(FeFn)

First-principles calculations predict that atomic iron (Fe) combines with fluorine (F) to produce stable molecular complexes having the form FeFn (n=1–6) and the species with n≥3 exhibit superhalogen properties. Electron affinities of the complexes are found to increase successively upto 8.20eV for FeF6. The unusual properties of these complexes are due to the involvement of inner shell 3d-electrons, which allow FeFn complexes to belong to the class of superhalogens and also due to the tendency of Fe to have valency that can exceed the value of 3. Quantum chemical calculations were carried out using an all-electron linear combination of atomic orbitals scheme within the density functional theory (DFT) framework utilizing the popular B3LYP (Becke, three-parameter, Lee–Yang–Parr) exchange correlation functional. Analysis of HOMO-LUMO gaps, molecular orbitals and binding energies of these complexes indicate that the FeFn complexes are stable. Population analysis of molecular orbitals was also carried out to determine the percentage (%) contribution of Fe and F atoms to the frontier orbitals (LUMO and HOMO). The orbital overlap population (OOP) diagrams provide information related to bonding and anti-bonding nature of overlap in the molecular orbitals. The principle of maximum hardness was applied to determine the relative stability of the complexes. Also, the stability and viability of novel salt series Li-(FeFn) has been tested by analyzing the molecules Li-(FeF4), Li-(FeF5) and Li-(FeF6) in detail.

How the hydrogen sorption properties of palladium are modified through interaction with iridium.

Hydrogen sorption (adsorption/absorption) in metals, in the form of thin films or nanoparticles, is a key process in the fields of energy storage and heterogeneous catalysis. Atomic hydrogen dissolved in the subsurface of a metal affects its surface atomic and electronic structures, and thereby its surface reactivity and catalytic properties. In addition, alloy effects modify both catalytic and hydrogen sorption phenomena. In order to rationalize recent experimental results showing the negative impact of hydrogen absorption on catalysis, the present article proposes an insight into structure-reactivity relationships through computational simulations, using density functional theory, of hydrogen sorption in the near-surface region of palladium atomic layers interacting with an iridium substrate. A detailed analysis of the electronic structure using local projected densities of states (PDOS) and crystal orbital overlap population (COOP) curves was carried out. It is found that the Pd/Ir system, with respect to pure Pd surfaces, keeps acceptable adsorption properties for surface reactions while preventing hydrogen penetration. The results of electronic structure calculations show that the most important difference between Pd and Ir is related to the strong anti-bonding character of the 1s-H/5p-Ir interaction, leading to the non-bonding character of the sp-Ir interaction with hydrogen. Thus, increasing the Ir concentration in a Pd-based system increases the anti-bonding contribution, which strongly weakens the overall metal-hydrogen interaction.

Comparative effectiveness of mepolizumab and omalizumab in severe asthma: An indirect treatment comparison

BackgroundSevere asthma is a heterogeneous disease. Patients with both eosinophilic and allergic asthma phenotypes may be eligible for treatment with mepolizumab and omalizumab. Evidence on the relative effectiveness of these treatments in this ‘overlap’ population would be informative for clinical and payer decision making. MethodsA systematic literature review and indirect treatment comparison (Bayesian framework) were performed to assess the comparative effectiveness and tolerability of mepolizumab and omalizumab, as add-ons to standard of care. Studies included in the primary analysis were double-blind, randomized controlled trials, ≥12 weeks' duration enrolling patients with severe asthma with a documented exacerbation history and receiving high-dose inhaled corticosteroids plus ≥1 additional controller. Two populations were examined: patients potentially eligible for 1) both treatments (Overlap population) and 2) either treatment (Trial population). ResultsIn the Overlap population, no differences between treatments in clinically significant exacerbations and exacerbations requiring hospitalization were found, although trends favored mepolizumab (rate ratio [RR]:0.66 [95% credible intervals (Crl):0.37,1.19]; 0.19[0.02,2.32], respectively). In the Trial population, mepolizumab treatment produced greater reductions in clinically significant exacerbations (RR:0.63 [95% CrI:0.45,0.89]) but not exacerbations requiring hospitalization compared with omalizumab (RR:0.58 [95% Crl: 0.16,2.13]), although the trend favored mepolizumab. Both treatments had broadly comparable effects on lung function, and similar tolerability profiles. ConclusionsWhilst this analysis has limitations due to a restricted evidence base and residual heterogeneity, it showed that in patients with severe asthma, mepolizumab seems to be at least as effective as omalizumab and that the tolerability profiles of the two treatments did not meaningfully differentiate.

First-principles investigation of mechanical and electronic properties of MFeAs (M = Cu, Li, and Na)

Mechanical and electronic properties of Cu2Sb-type compounds MFeAs (M = Cu, Li, and Na) have been studied by the first-principles calculations. The main trends in structure parameters, mechanical parameters, electronic bands, and densities of states (DOS) for MFeAs are analyzed according to the variable cation M sites. Our results show that the lattice constants increase, while the bulk modulus, shear modulus, and Young's modulus decrease with the increasing radii of M sites in the sequence CuFeAs → LiFeAs → NaFeAs. Mulliken overlap population indicates that different M atoms in MFeAs (M = Cu, Li, and Na) would influence the bond nature of Fe-As, which may induce the superconductivity. The disappearance of the hole-pockets affects the superconductivity in CuFeAs. Although the value of the DOSs N(EF) at the Fermi level grows with decreasing radii of M sites, it is not the only factor influencing the superconductivity. Due to the repulsive interaction between Cu-3d and Fe-3d states in CuFeAs phase, it would change the position of Fe-3d orbits and Fermi energy level after introducing Cu in this structure. Therefore, after introducing Cu in the structure would induce the different position of Fe-3d states and Fermi energy level. Therefore, we believe that the component M has an important influence on the superconductivity.

Establishing and Understanding Adsorption-Energy Scaling Relations with Negative Slopes.

Adsorption-energy scaling relations are widely used for the design of catalytic materials. To date, only linear scaling relations are known in which the slopes are positive. Considering the adsorption energies of F, O, N, C, and B on transition metals, we show here that scaling relations with negative slopes also exist between certain adsorbates. The origin of such unconventional scaling relations is analyzed in terms of common descriptors such as d-band center, work function, number of outer electrons, electronic charge on the adsorbates, integrated crystal orbital overlap populations, and crystal orbital Hamilton populations. Conventional scaling relations are formed between adsorbates such as F, O, N, and C, which create ionic-like bonds with surfaces. Conversely, anomalous scaling relations are established between those and covalently bound adsorbates such as B. This widens the theory of adsorption-energy scaling relations and opens new avenues in physical chemistry and catalysis, for instance, in direct borohydride fuel cells.

Density functional theory calculations on transition metal atoms adsorbed on graphene monolayers

Transition metal atom adsorption on graphene monolayers has been elucidated using periodic density functional theory under hybrid and generalized gradient approximation functionals. More specifically, we examined the adsorption of Cu, Fe, Zn, Ru, and Os on graphene monolayers by calculating, among others, the electronic density-of-states spectra of the adatom-graphene system and the overlap populations of the adatom with the nearest adsorbing graphene carbon atoms. These calculations reveal that Cu form primarily covalent bonds with graphene atoms via strong hybridization between the adatom orbitals and the sp band of the graphene substrate, whereas the interaction of the Ru and Os with graphene also contain ionic parts. Although the interaction of Fe with graphene atoms is mostly covalent, some charge transfer to graphene is also observed. The interaction of Zn with graphene is weak. Mulliken population analysis and charge contour maps are used to elucidate charge transfers between the adatom and the substrate. The adsorption strength is correlated with the metal adsorption energy and the height of the metal adatom from the graphene plane for the geometrically optimized adatom-graphene system. Our analysis shows that show that metal adsorption strength follows the adatom trend Ru≈Os>Fe>Cu>Zn, as verified by corresponding changes in the adsorption energies. The increased metal-carbon orbital overlap for the Ru relative to Os adatom is attributed to hybridization defects.

A combined experimental and DFT investigation of disazo dye having pyrazole skeleton

Disazo dye containing pyrazole skeleton has been synthesized. The structure of the dye has been confirmed by using FT-IR, 1H NMR, 13C NMR, HRMS spectral technique and elemental analysis. The molecular geometry and infrared spectrum are also calculated by the Density Functional Theory (DFT) employing B3LYP level with 6-311G (d,p) basis set. The chemical shifts calculation for 1H NMR of the title molecule is done by using by Gauge-Invariant Atomic Orbital (GIAO) method by utilizing the same basis sets. The total density of state, the partial density of state and the overlap population density of state diagram analysis are done via Gauss Sum 3.0 program. Frontier molecular orbitals such as highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) and molecular electrostatic potential surface on the title molecule are predicted for various intramolecular interactions that are responsible for the stabilization of the molecule. The experimental results and theoretical values have been compared.

Quaternary Germanides RE3TRh4Ge4 (RE = Ce, Pr, Nd; T = Nb, Ta) – A New Coloring Variant of the Aristotype AlB2

AbstractThe quaternary germanides RE3TRh4Ge4 (RE = Ce, Pr, Nd; T = Nb, Ta) were synthesized from the elements by arc‐melting and subsequent annealing in a muffle furnace. The structure of Ce3TaRh4Ge4 was refined from single‐crystal X‐ray diffractometer data: new type, Pbam, a = 719.9(2), b = 1495.0(3), c = 431.61(8), wR2 = 0.0678, 1004 F2 values, and 40 variables. Isotypy of the remaining phases was evident from X‐ray powder patterns. Ce3TaRh4Ge4 is a new superstructure variant of the aristotype AlB2 with an ordering of cerium and tantalum on the aluminum site, whereas the honey‐comb network is built up by a 1:1 ordering of rhodium and germanium. This crystal‐chemical relationship is discussed based on a group‐subgroup scheme. The distinctly different size of tantalum and cerium leads to a pronounced puckering of the [Rh4Ge4] network, which shows the shortest interatomic distances (253–271 pm Rh–Ge) within the Ce3TaRh4Ge4 structure. Another remarkable structural feature concerns the tantalum coordination with six shorter Ta–Rh bonds (265–266 pm) and six longer Ta–Ge bonds (294–295 pm). The [Rh4Ge4] network fully separates the tantalum and cerium atoms (Ce–Ce > 387 pm, Ta–Ta > 431 pm, and Ce–Ta > 359 pm). The electronic density of states DOS from DFT calculations show metallic behavior with large contributions of localized Ce 4f as well as itinerant ones from all constituents at the Fermi level but no significant magnetic polarization on Ce could be identified. The bonding characteristics described based on overlap populations illustrate further the crystal chemistry observations of the different coordination of Ce1 and Ce2 in Ce3TaRh4Ge4. The Rh–Ge interactions within the network are highlighted as dominant. The bonding magnitudes follow the interatomic distances and identify differences of Ta bonding vs. Ce1/Ce2 bonding with the Rh and Ge substructures.

Predicting the structural and electronic properties of transition metal monoxides from bulk to surface morphology

We systematically investigate the structural, electronic and magnetic properties, bonding analysis, as well as surface morphology of transition metal monoxides (FeO, CoO and NiO) utilizing density functional theory (DFT) with various functionals across from GGA to GGA+U and hybrid functional. Our results reveal that the screened hybrid functional (HSE) could give a reasonable description on structural and electronic properties of these strongly correlated systems when compared to experiments. Local approximation GGA functional fails to yield the accuracy band gaps. GGA+U approximation are rational when given a reasonable U, but the U which reproduce a reasonable band gap often yield a significant error in describing other properties such as lattice constant or magnetic moment. The computed Crystal Orbital Overlap Population (COOP) indicates that cubic FeO and CoO are metastable phase, while the distortion occurs to enhance stability. Based on the reliable functional, the surface morphology of FeO, CoO and NiO are predicted using Wulff construction approach.