scholarly journals Influence of water on the surface of graphene

2018 ◽  
Vol 174 ◽  
pp. 06002
Author(s):  
Yunus Kaya ◽  
Yalçin Kalkan ◽  
Rob Veenhof
Keyword(s):  
Density Functional Theory ◽  
Water Molecule ◽  
Density Functional ◽  
Theoretical Models ◽  
Surface Conductivity ◽  
Basis Set ◽  
Hybrid Functional ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Influence Of Water

We have studied how water modifies the surface of graphene and in particular how the surface conductivity of graphene is affected. According to the literature, two types of interactions should be distinguished: physical, where a water molecule remains intact and is located at some distance from the mesh, and chemical, where a water molecule is imbricated in the graphene bond structure. We have developed theoretical models for both types of interactions using the density functional theory (DFT) with the B3LYP hybrid functional combined with the 6-31G(d) basis set. Our calculations show that the surface conductivity of graphene is reduced in the presence of water.

A Density Functional Theory Study of the Isomerization of Substituted 2and#39;-hydroxychalcones to the Corresponding Flavanones

2021 ◽  
Vol 43 (1) ◽  
pp. 25-25
Author(s):  
Said Abdelqadar Said Said Abdelqadar Said ◽  
Omar A Shareef and Abdulkhalik S Alkazzaz Omar A Shareef and Abdulkhalik S Alkazzaz
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Ring Closure ◽  
Basis Set ◽  
Functional Theory ◽  
Rate Determining Step ◽  
The Density Functional Theory ◽  
Electronic And Structural Properties ◽  
Maximum Hardness Principle

The transformation of 2and#39;-hydroxychalcones to their corresponding flavanones was studied theoretically by the use of the density functional theory (DFT) with B3-LYP/ 6-311G basis set to get important information about the role of both of electronic and structural properties in this process. The obtained energies were found to be in agreement with our previous results that obtained from HPLC studies. The estimated hardness, polarizability, and electrophilicity profiles were found to obey the maximum hardness principle (MHP), minimum polarizability principle (MPP), and the minimum electrophilicity principle (MEP) respectively. Flavanone ring closure was found to be the rate-determining step.

scholarly journals Analysis of vibratinal spectra of 8-hydroxyquinoline and its 5,7-dichloro, 5,7-dibromo, 5,7-diiodo and 5,7-dinitro derivatives based on density functional theory calculations

2007 ◽  
Vol 5 (1) ◽  
pp. 201-220 ◽  
Author(s):  
Khaled Bahgat ◽  
Abdel Ragheb
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Basis Set ◽  
Normal Coordinate ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Vibrational Bands ◽  
Good Agreement

AbstractThe geometry, frequency and intensity of the vibrational bands of 8-hydroxyquinoline and its 5,7-dichloro, 5,7-dibromo, 5,7-diiodo and 5,7-dinitro derivatives were obtained by the density functional theory (DFT) calculations with Becke3-Lee-Parr (B3LYP) functional and 6-31G* basis set. The effects of chloride, bromide, iodide and nitro substituent on the vibrational frequencies of 8-hydroxyquinoline have been investigated. The assignments have been proposed with aid of the results of normal coordinate analysis. The observed and calculated spectra are found to be in good agreement.

A Density Functional Theory Study of the Isomerization of Substituted 2and#39;-hydroxychalcones to the Corresponding Flavanones

2021 ◽  
Vol 43 (1) ◽  
pp. 25-25
Author(s):  
Said Abdelqadar Said Said Abdelqadar Said ◽  
Omar A Shareef and Abdulkhalik S Alkazzaz Omar A Shareef and Abdulkhalik S Alkazzaz
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Ring Closure ◽  
Basis Set ◽  
Functional Theory ◽  
Rate Determining Step ◽  
The Density Functional Theory ◽  
Electronic And Structural Properties ◽  
Maximum Hardness Principle

The transformation of 2and#39;-hydroxychalcones to their corresponding flavanones was studied theoretically by the use of the density functional theory (DFT) with B3-LYP/ 6-311G basis set to get important information about the role of both of electronic and structural properties in this process. The obtained energies were found to be in agreement with our previous results that obtained from HPLC studies. The estimated hardness, polarizability, and electrophilicity profiles were found to obey the maximum hardness principle (MHP), minimum polarizability principle (MPP), and the minimum electrophilicity principle (MEP) respectively. Flavanone ring closure was found to be the rate-determining step.

scholarly journals Comprehensive Density Functional Theory Studies of Vibrational Spectra of Carbonates

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2275
Author(s):  
Yurii N. Zhuravlev ◽  
Victor V. Atuchin
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Predictive Power ◽  
Hybrid Functional ◽  
Program Code ◽  
Functional Theory ◽  
Carbonate Solutions ◽  
The Density Functional Theory ◽  
Bending Mode ◽  
Cation Radius

Within the framework of the density functional theory (DFT) and the hybrid functional B3LYP by means of the CRYSTAL17 program code, the wavenumbers and intensities of normal oscillations of MgCO3, CaCO3, ZnCO3, CdCO3 in the structure of calcite; CaMg(CO3)2, CdMg(CO3)2, CaMn(CO3)2, CaZn(CO3)2 in the structure of dolomite; BaMg(CO3)2 in the structure of the norsethite type; and CaCO3, SrCO3, BaCO3, and PbCO3 in the structure of aragonite were calculated. Infrared absorption and Raman spectra were compared with the known experimental data of synthetic and natural crystals. For lattice and intramolecular modes, linear dependences on the radius and mass of the metal cation are established. The obtained dependences have predictive power and can be used to study solid carbonate solutions. For trigonal and orthorhombic carbonates, the linear dependence of wavenumbers on the cation radius RM (or M–O distance) is established for the infrared in-plane bending mode: 786.2–65.88·RM and Raman in-plane stretching mode: 768.5–53.24·RM, with a correlation coefficient of 0.87.

A Density Functional Theory Study of the Isomerization of Substituted 2'-hydroxychalcones to the Corresponding Flavanones

2021 ◽  
Vol 43 (1) ◽  
pp. 25-25
Author(s):  
Said Abdelqadar Said Said Abdelqadar Said ◽  
Omar A Shareef and Abdulkhalik S Alkazzaz Omar A Shareef and Abdulkhalik S Alkazzaz
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Ring Closure ◽  
Basis Set ◽  
Functional Theory ◽  
Rate Determining Step ◽  
The Density Functional Theory ◽  
Electronic And Structural Properties ◽  
Maximum Hardness Principle

The transformation of 2'-hydroxychalcones to their corresponding flavanones was studied theoretically by the use of the density functional theory (DFT) with B3-LYP/ 6-311G basis set to get important information about the role of both of electronic and structural properties in this process. The obtained energies were found to be in agreement with our previous results that obtained from HPLC studies. The estimated hardness, polarizability, and electrophilicity profiles were found to obey the maximum hardness principle (MHP), minimum polarizability principle (MPP), and the minimum electrophilicity principle (MEP) respectively. Flavanone ring closure was found to be the rate-determining step.

A Density Functional Theory Study of the Isomerization of Substituted 2and#39;-hydroxychalcones to the Corresponding Flavanones

2021 ◽  
Vol 43 (1) ◽  
pp. 25-25
Author(s):  
Said Abdelqadar Said Said Abdelqadar Said ◽  
Omar A Shareef and Abdulkhalik S Alkazzaz Omar A Shareef and Abdulkhalik S Alkazzaz
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Ring Closure ◽  
Basis Set ◽  
Functional Theory ◽  
Rate Determining Step ◽  
The Density Functional Theory ◽  
Electronic And Structural Properties ◽  
Maximum Hardness Principle

The transformation of 2and#39;-hydroxychalcones to their corresponding flavanones was studied theoretically by the use of the density functional theory (DFT) with B3-LYP/ 6-311G basis set to get important information about the role of both of electronic and structural properties in this process. The obtained energies were found to be in agreement with our previous results that obtained from HPLC studies. The estimated hardness, polarizability, and electrophilicity profiles were found to obey the maximum hardness principle (MHP), minimum polarizability principle (MPP), and the minimum electrophilicity principle (MEP) respectively. Flavanone ring closure was found to be the rate-determining step.

Conformational, vibrational and electronic properties of CH3(CH2)3CX2NH2 (X = H, F, Cl or Br): Halogen and solvent effects

2015 ◽  
Vol 14 (04) ◽  
pp. 1550031
Author(s):  
Cemal Parlak ◽  
Münevver Gökce ◽  
Mahir Tursun ◽  
Lydia Rhyman ◽  
Ponnadurai Ramasami
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Density Functional ◽  
Basis Set ◽  
Chemical Hardness ◽  
Uv Spectrum ◽  
Dft Methods ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Td Dft

The effects of varying halogen and solvent, in terms of vibrational and electronic properties, on the different conformers of 1-pentanamine [ CH 3( CH 2)4 NH 2] and 1,1-dihalogeno-pentan-1-amines [ CH 3( CH 2)3 CX 2 NH 2; X = F , Cl or Br ] were investigated by employing the density functional theory (DFT) and time-dependent density functional theory (TD-DFT) methods. The B3LYP functional was used with the 6-31++G(d,p) basis set. Computations were focused on the 10 conformational isomers of the compounds in the gas phase and both in non-polar (benzene) and polar (methanol) solvents. The present work explores the effects of the halogen and the medium on the conformational preference, and geometrical parameter, dipole moment, NH 2 vibrational frequency, UV spectrum, highest occupied and lowest unoccupied molecular orbitals (HOMO–LUMO) orbital and DOS diagram of the conformers. The atypical characteristics of fluorine and bromine affecting the electrical bandgap, chemical hardness, electronegativity, PDOS or OPDOS plots and the absorption band are observed correspondingly. The findings of this work can be useful to those systems involving changes in the conformations analogous to the compounds studied.

Influence of water on the CH3O˙ + O2 → CH2O + HO2˙ reaction

2019 ◽  
Vol 21 (28) ◽  
pp. 15734-15741 ◽  
Author(s):  
Subhasish Mallick ◽  
Amit Kumar ◽  
Brijesh Kumar Mishra ◽  
Pradeep Kumar
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Water Molecule ◽  
Density Functional ◽  
Electronic Structure Calculations ◽  
Functional Theory ◽  
Influence Of Water ◽  
Single Water Molecule ◽  
Structure Calculations

Electronic structure calculations employing density functional theory have been used to study the effect of a single water molecule on the CH3O˙ + O2 → CH2O + HO2˙ reaction.

scholarly journals A Simplified Approach to the Density Functional Theory of Molecules

1999 ◽  
Vol 54 (2) ◽  
pp. 101-109 ◽  
Author(s):  
Christian Kollmar
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Atomic Orbital ◽  
Basis Set ◽  
Electronic Density ◽  
Functional Theory ◽  
Simplified Approach ◽  
Secular Matrix ◽  
The Density Functional Theory ◽  
Definition Of

Abstract A simplified molecular orbital (MO) formalism based on density functional theory is developed. Starting from the same energy expression as Kohn-Sham theory the electronic density is expanded in terms of atomic mono-center densities. Application of the variational principle leads to a secular matrix with a particularly transparent structure which allows the definition of a resonance integral taking into account the effect of interference in a natural way. The construction of the secular matrix scales formally as N2 instead of N3 in the Kohn-Sham formalism with N being the dimension of the atomic orbital (AO) basis set.

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