scholarly journals The Hydrogen Passivated Graphene Cluster and its Stability - First Principle DFT (B3LYP) Levels of Approximation with the Basis Set 3-21G

2018 ◽  
Vol 1 (1) ◽  
pp. 5-10
Author(s):  
Debendra Baniya
Keyword(s):  
Binding Energy ◽  
Carbon Atom ◽  
State Energy ◽  
Population Analysis ◽  
Basis Set ◽  
Mulliken Population ◽  
B3lyp Level ◽  
Reported Data ◽  
Homo Lumo ◽  
Graphene Cluster

First-principles DFT (B3LYP) levels of calculations with the basis set 3-21G have been carried out in order to study the geometric stability and electronic properties of hydrogen passivated graphene (H-graphene) clusters(CN) (where N = 6, 10, 13, 16, 22, 24, 27, 30, 35, 37, 40, 42, 45, 47, 48, 50, 52, 54, 70 and 96) and perform the DOS spectrum on H-graphene (C16H10, C24H12, C30H14, C48H18, C70H22 and C96H24) using Mulliken population analysis by the Gaussian 03 W set of programs. The variations of ground state energy of graphene clusters are observed on sizes and corresponding number of carbon atoms. The binding energy per carbon atom is the function of carbon atoms for the number of carbon atoms less than 30 and saturated at carbon’s number 30 and more in the DFT (B3LYP) levels of approximation with the basis set 3-21G. The binding energy per carbon atom of a pure graphene sheet C32 is 8.03 eV/atom in the DFT (B3LYP) level of approximation with the choice of the basis set 3-21G, which is acceptable with previous reported data 7.91 eV/atom. The HOMO-LUMO gap in NBO is studied for some H-grapheneclustors C16H10, C24H12, C30H14, C48H18, C70H22 and C96H24.

First-principles study of the stability of graphene and adsorption of halogen atoms (F, Cl and Br) on hydrogen passivated graphene

2014 ◽  
Vol 28 (21) ◽  
pp. 1450141 ◽  
Author(s):  
D. B. Karki ◽  
N. P. Adhikari
Keyword(s):  
Binding Energy ◽  
Carbon Atom ◽  
First Principles ◽  
Cluster Size ◽  
Energy Gap ◽  
Lumo Energy ◽  
Halogen Atoms ◽  
The Stability ◽  
Homo Lumo ◽  
Graphene Cluster

First-principles calculations based on Hartree–Fock (HF) and density functional theory (DFT) levels of approximation have been carried out in order to study the stability of graphene clusters as a function of number of carbon atoms (N). The variation of calculated binding energy per carbon atom with corresponding number of carbon atoms (N) in graphene cluster almost saturates after the cluster size consisting of 96 carbon atoms, with binding energy per carbon atom 8.24 eV/atom. Adsorption of halogen atoms, ( F , Cl and Br ), on hydrogen passivated graphene ( H -graphene) was also studied systematically through first-principles DFT calculations by taking five different H -graphene clusters. The calculations showed that the most stable adsorption site for halogen adatoms on H -graphene being T site with binding energy 2.41 eV ( F ), 1.48 eV ( Cl ) and 1.19 eV ( Br ) on the H -graphene cluster consisting 96 carbon atoms. Moreover, on increasing the size of H -graphene cluster, the binding energy of halogen adatoms found to be increasing. The distances of adatom from the nearest carbon atom of H -graphene sheet were 1.47 Å ( F ), 2.71 Å ( Cl ) and 3.01 Å ( Br ), however, the adatom heights from the H -graphene basal plane were 2.22 Å ( F ), 2.90 Å ( Cl ), and 3.19 Å ( Br ). The bonding of halogen adatoms on H -graphene were through the charge transfer; 0.30 | e | ( F ), 0.37 | e | ( Cl ) and 0.19 | e | ( Br ), from H -graphene to adatoms and includes the negligible local distortion in the underlying planner H -graphene. Charge redistribution upon adsorption induces significant dipole moments 2.16 D ( F ), 4.81 D ( Cl ) and 3.08 D ( Br ) on H -graphene. The calculated HOMO–LUMO energy gap of adatom- H -graphene and H -graphene does not differ significantly up to the cluster size N = 30, however, beyond N = 30 adsorption of halogen adatoms significantly opens the HOMO–LUMO energy gap on H -graphene and the opening of HOMO–LUMO energy gap also saturates from N = 96. Correlation of computed HOMO–LUMO energy gap and corresponding binding energy of adatom- H -graphene systems have been also studied.

DFT investigation on interaction of chlorine with In2O3 nanostructures

2015 ◽  
Vol 93 (11) ◽  
pp. 1249-1260 ◽  
Author(s):  
V. Nagarajan ◽  
R. Chandiramouli
Keyword(s):  
Density Functional ◽  
Energy Gap ◽  
Population Analysis ◽  
Average Energy ◽  
Adsorption Properties ◽  
Basis Set ◽  
Mixed Gas ◽  
Mulliken Population ◽  
Adsorption Sites ◽  
Homo Lumo

The structural, electronic, and adsorption properties of chlorine on pristine, tin-, aluminum-, and fluorine-substituted In2O3 nanostructures are successfully optimized and computed using density functional theory along with the B2LYP/LanL2DZ basis set. The electronic properties of pristine, tin-, aluminum-, and fluorine-substituted In2O3 nanostructures are discussed in terms of ionization potential, HOMO–LUMO gap, and electron affinity. The dipole moment and point symmetry group of In2O3 nanostructures are also reported. The structural stability of pristine, tin-, aluminum-, and fluorine-substituted In2O3 nanostructures are investigated in terms of formation energy. The adsorption properties of chlorine on In2O3 are studied and the most appropriate adsorption sites of Cl2 on In2O3 nanostructures are reported. The adsorption properties of hydrogen on In2O3 nanostructures are also investigated and inferred that In2O3 exhibits good sensing characteristics towards hydrogen. The adsorbed energy, HOMO–LUMO gap, Mulliken population analysis, and average energy gap variation are used to identify the prominent adsorption site of Cl2 on In2O3 material. The substitution of fluorine in In2O3 nanostructures enhances the Cl2 adsorption properties in the mixed gas atmosphere.

Structures, electronic and magnetic properties of the MnnS and Mnn−1S2 (n = 1–6) clusters

2019 ◽  
Vol 33 (22) ◽  
pp. 1950254 ◽  
Author(s):  
Zhi Li ◽  
Zhen Zhao ◽  
Qi Wang ◽  
Tong-Tong Shi
Keyword(s):  
Magnetic Properties ◽  
Ground State ◽  
First Principles ◽  
Steel Industry ◽  
Population Analysis ◽  
Total Spin ◽  
Spontaneous Generation ◽  
Mulliken Population ◽  
Electronic And Magnetic Properties ◽  
Homo Lumo

To understand sulfide inclusions in the steel industry, the structures, stabilities, electronic and magnetic properties of the Mn[Formula: see text]S and Mn[Formula: see text]S2 (n=1–6) clusters are investigated by using first-principles. The results show that the S atoms prefer to occupy the outside surface center of the Mn[Formula: see text] (n = 3–6) clusters. Chiral isomers are occurred to the Mn5S2 isomers. The Mn2S, Mn2S2 clusters are more stable than their neighbors. However, the MnS, S2, and Mn5I2 clusters possess higher dynamic stability than their neighbors by the HOMO–LUMO gaps. The Mn[Formula: see text]S and Mn[Formula: see text]S2 (n = 1–6) clusters prefer to spontaneous generation by Gibbs free energy. A few 4s orbital electrons of Mn atoms transferred to the S atoms by Mülliken population analysis. For the other Mn[Formula: see text]S (n = 1–6) clusters, the spin density (17.256) of the ground-state Mn6S clusters is the largest. For the Mn[Formula: see text]S2 (n = 1–6) clusters, the total spin (9.604) of the ground-state Mn2S2 cluster is the largest.

scholarly journals Density Functional Calculations on the Molecular, Electronic Structures of Metal-Free, N,N'-Dideuterio and Magnesium Tetra-3,4-Pyridino-Porphyrazines

2019 ◽  
pp. 40-44
Author(s):  
Zhongqiang Liu ◽  
Xianxi Zhang
Keyword(s):  
Electronic Structures ◽  
Density Functional ◽  
Atomic Charge ◽  
Substitution Effect ◽  
Membered Ring ◽  
Basis Set ◽  
Metal Free ◽  
B3lyp Level ◽  
Homo Lumo ◽  
Optimized Geometries

A theoretical calculation of the fully optimized geometries and electronic structures of the metal-free Tetra-2,3-Pyridino-Porphyrazine (TPdPzH2*), N,N-Dideuterio (TPdPzD2*), and Magnesium (TPdPzMg*) tetra-3,4-pyridino-porphyrazine has been conducted with the density functional B3LYP level using the 6-31G(d) basis set. A comparison among the different Phthalocyanine (Pc) derivatives, including Tetra-2,3-Pyridino-Porphyrazine (TPdPzH2) compounds, for the geometry, molecular orbital, and atomic charge was made. The substitution effect of the N atoms and the isotopic effect of D atoms on the properties of these compounds were discussed. The farther the heterocyclic N atoms in the benzo rings from 16-membered ring are, the smaller it influence the size of the central hole, the bond lengths and bond angles of 16-membered ring, the HOMO-LUMO gaps, and the atomic charges on the core Pz fragment. In other words, the properties of TPdPz* compounds are closer to Pc than TPdPz. With the order of H2Pc<TPdPzH2<TPdPzH2*, the acidity of the inner N-H bonds in the three molecules increased in turn.

Structural, vibrational (FTIR and FT-Raman), NMR, UV–vis spectral analysis, and DFT study of 2-(6-oxo-2-thioxotetrahydropyrimidin-4(1H)-ylidene) hydrazine carboxamide

2017 ◽  
Vol 95 (5) ◽  
pp. 580-589 ◽  
Author(s):  
N. Kalaiarasi ◽  
S. Manivarman
Keyword(s):  
Density Functional ◽  
Nbo Analysis ◽  
Basis Set ◽  
Geometrical Parameters ◽  
Mulliken Population ◽  
Functional Theory ◽  
Charge Delocalization ◽  
Homo Lumo ◽  
Spectral Characterizations ◽  
Ft Raman

Vibrational and spectral characterizations of 2-(6-oxo-2-thioxo tetrahydro pyrimidin-4(1h)-ylidene) hydrazine carboxamide (OTHHPYHC) were experimentally presented for the ground state using FTIR and FT-Raman and theoretically presented by density functional theory (DFT) using B3LYP correlation function with the basis set 6-31G(d,p). The geometrical parameters, energies, and wavenumbers have been obtained. The fundamental assignments were performed on the basis of total energy distribution. The first order hyperpolarizability (β0) and relative properties (β, α0, and Δα) were calculated using B3LYP/6-31G(d, p) method. Solidity of the molecule due to hyperconjugative interactions and charge delocalization has been analysed using natural bond orbital (NBO) analysis. The charge distribution and electron transfer from bonding to antibonding orbitals and electron density in the σ* and π* antibonding orbitals confirms interaction within the molecule. In addition to this, Mulliken population and HOMO–LUMO analysis have been used to support the information of structural properties.

Density functional theory study of the geometrical and electronic structures of GenV(0,±1)(n=1–9) clusters

2017 ◽  
Vol 31 (05) ◽  
pp. 1750022 ◽  
Author(s):  
Shun-Ping Shi ◽  
Yi-Liang Liu ◽  
Bang-Lin Deng ◽  
Chuan-Yu Zhang ◽  
Gang Jiang
Keyword(s):  
Density Functional Theory ◽  
Natural Population ◽  
Density Functional ◽  
Population Analysis ◽  
Basis Sets ◽  
Functional Theory ◽  
Natural Population Analysis ◽  
B3lyp Level ◽  
Calculation Results ◽  
Homo Lumo

Geometrical and electronic properties of Ge[Formula: see text]V[Formula: see text] clusters containing 1–9 Ge atoms and one V atom are calculated by using density functional theory (DFT) at the B3LYP level and the LanL2DZ basis sets. The growth pattern behavior, natural population analysis, relative stability, electronic property and magnetism of these clusters are discussed in detail. The calculation results of the geometrical show that the relative stable structures of Ge[Formula: see text]V[Formula: see text] clusters adopt 3D structures from [Formula: see text] to [Formula: see text]. The results of natural population analysis show that electrons transfer from the Ge atoms to the V atoms when [Formula: see text] while the electrons transfer from the V atoms to the Ge atoms when [Formula: see text]. The Ge[Formula: see text]V[Formula: see text] clusters possess higher stability and the GeV[Formula: see text], Ge3V[Formula: see text], Ge5V[Formula: see text], Ge7V[Formula: see text], and Ge9V[Formula: see text] have larger HOMO–LUMO gaps. Furthermore, the VIPs of Ge[Formula: see text]V clusters show a reverse trend in contrast to the AIPs.

Study of Adsorption Properties of O2, CO2, NO2 and SO2 on Si-Doped Carbon Nanotube Using Density Functional Theory

2011 ◽  
Vol 110-116 ◽  
pp. 315-320
Author(s):  
M. R. Sonawane ◽  
B. J. Nagare
Keyword(s):  
Density Functional Theory ◽  
Charge Transfer ◽  
Carbon Nanotube ◽  
Binding Energy ◽  
Density Of States ◽  
Density Functional ◽  
Population Analysis ◽  
Energy Charge ◽  
Basis Set ◽  
Functional Theory

We report reactivity of silicon doped single walled carbon nanotube (Si-CNT) towards the small atmospheric gas molecules O2, CO2, SO2and NO2using density functional theory based on the numerical basis set method. The reactivity of these molecules is explained on the basis of electronic properties such as binding energy, charge density, charge transfer and density of states. The large change in binding energy and formation of sigma (σ) bonds between silicon and oxygen atoms shows the strong chemisorption of the molecules on Si-CNT. Further, the density of states analysis clearly illustrate the reduction in the band gap and creation of extra state near the Fermi level, which acts as a catalytic center for adsorption of the molecules. The Mulliken population analysis indicates the charge transfer from Si-CNT to the molecules due to their more electronegativity.

X-ray and DFT Investigation of (E)-4-bromo-5-methoxy-2-((o-tolylimino)methyl)phenol Compound

2018 ◽  
pp. 454-461
Keyword(s):  
Density Functional ◽  
Theoretical Calculations ◽  
Population Analysis ◽  
Diffraction Method ◽  
Dft Method ◽  
Basis Set ◽  
X Ray Diffraction ◽  
Mulliken Population ◽  
Charge Delocalization ◽  
X Ray

(E)-4-bromo-5-methoxy-2-((o-tolylimino)methyl)phenol was investigated by experimental and theoretical methodologies. The solid state molecular structure was determined by X-ray diffraction method. All theoretical calculations were performed by density functional theory (DFT) method by using B3LYP/6-31G(d,p) basis set. The titled compound showed the preference of enol form, as supported by X-ray diffraction method. The geometric and molecular properties were compaired for both enol-imine and keto-amine forms for title compound. Stability of the molecule arises from hyperconjugative interactions, charge delocalization and intramolecular hydrogen bond has been analyzed using natural bond orbital (NBO) analysis. Mulliken population method and natural population analysis (NPA) have been studied. Also, condensed Fukui function and relative nucleophilicity indices calculated from charges obtained with orbital charge calculation methods (NPA). Molecular electrostatic potential (MEP) and non linear optical (NLO) properties are also examined.

Population Analysis with Hydrogen 2 p Polarization Functions Included in the INDO Basis Set

1980 ◽  
Vol 35 (12) ◽  
pp. 1350-1353
Author(s):  
J. C. Facelli ◽  
R. H. Contreras
Keyword(s):  
Ab Initio ◽  
Population Analysis ◽  
Basis Set ◽  
Ab Initio Methods ◽  
Mulliken Population Analysis ◽  
Indo Method ◽  
Hydrogen Atoms ◽  
Mulliken Population ◽  
Electron Population ◽  
Polarization Functions

Abstract Mulliken population analysis with 2p polarization functions included in the AO basis set of the INDO method has been performed for a set of molecules containing hydrogen as well as first row atoms. It is found that this enlargement of the basis set yields an increasing electron population in hydrogen atoms, in agreement with trends found in “ab initio” methods.

THEORETICAL STUDY OF NEUTRAL AND IONIC SinO(n = 1-13) CLUSTERS

2009 ◽  
Vol 23 (18) ◽  
pp. 3729-3738
Author(s):  
YU-HONG ZHU ◽  
BAO-XING LI ◽  
FANG-SHU LIANG ◽  
JIE XU
Keyword(s):  
Density Functional ◽  
Theoretical Study ◽  
Dipole Moments ◽  
Basis Set ◽  
Electronic Charge ◽  
Full Potential ◽  
Mulliken Population ◽  
Consistent Field ◽  
Self Consistent Field ◽  
Homo Lumo

A systematic theoretical study of the structural properties and stabilities for neutral Si n O (n = 1-13) clusters and their ions has been carried out using the full-potential linear-muffin-tin-orbital molecular-dynamics (FP-LMTO-MD) method and the Amsterdam Density Functional (ADF) program with TZ2P basis set in conjunction with self-consistent field (SCF). Their ionization potentials (IPs), electron affinities (EAs), dipole moments μ, constant volume heat capacity Cv are computed. Based on the Mulliken population analyses, it is found that part of electronic charge is transferred from the Si atoms into the oxygen atom. Compared with other structures, the adsorption structures with an edge or a surface O atom are more stable. Calculations also show that the Si n O clusters with larger HOMO–LUMO gap exhibit high stability.

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