scholarly journals Theoretical investigations of ZnO/CdO material – A DFT approach

2018 ◽  
Vol 6 (1) ◽  
pp. 79
Author(s):  
Rackesh Jawaher ◽  
Indirajith R ◽  
Krishnan S ◽  
Bharanidharan Bharani ◽  
Robert R ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Dihedral Angles ◽  
Atomic Charges ◽  
First Order ◽  
Nlo Property ◽  
Theoretical Investigations ◽  
Title Molecule ◽  
Homo Lumo

The theoretical investigations of ZnO/CdO material were carried out by using ab initio calculations. The bond parameters such as bond lengths, bond angles and dihedral angles were calculated at DFT/B3LYP/LANL2DZ level of theory. The NLO property of the title molecule was calculated using a first order hyperpolarizability calculation. NBO study reveals that the hyperconjucative interactions between the material. Homo-Lumo analysis the charge transfer occurs within the molecule. MEP surface predicts the reactive sites of the present molecule. In addition of Mulliken atomic charges and thermodynamic parameters were also plotted and calculated.

ab initio MO Optimization of Molecular Structures of Fluoro- and Chloro-Substituted Dibenzo-p-dioxines and the Effect of Halogen Substitution at the 2,3,7,8-Positions on Metabolic Attack

1997 ◽  
Vol 52 (11) ◽  
pp. 1418-1431 ◽  
Author(s):  
Roland Weber ◽  
Till Kühn ◽  
Hanspaul Hagenmaier ◽  
Günter Häfelinger
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Energy Gap ◽  
Substituent Effects ◽  
Molecular Structures ◽  
X Ray ◽  
Degree Pattern ◽  
Chlorine Substituent ◽  
Homo Lumo ◽  
Good Agreement

Full ab initio optimizations were performed on the molecular structures of 24 fluorinated and chlorinated dibenzodioxines (PFDD/PCDD ) and dibenzofurans (PFDF/PCDF). Reasonable agreement was found by comparing the geometries of four calculated structures with known X-ray data from the literature. For the fluorine substituent, calculated electron densities (Mulliken total charges and π-electron charges) clearly demonstrate the opposite influence of the inductive (I) and mesomeric (M) effect. The changes in π-densities at carbons in ortho-, meta- and para-position are constant for each fluorine substituent (independent of degree, pattern, and position of substitution). It is thus possible to calculate the π-densities of the substituted dioxines by increments starting from dibenzodioxine. π-Charges from quantum mechanical calculations and the increment system show good agreement even for OctaFDD (O8FDD ), where eight substituent effects are acting additively. Compared with fluorine, the chlorine substituent exercises a smaller -I-effect and a clearly weaker +M-effect. The HOMO coefficients of the unsubstituted dibenzodioxine and dibenzofuran, extracted from ab initio calculations, yield a good explanation for the observed regioselective metabolic attack at the 2,3,7,8-positions. The squares of the HOMO-coefficients of the 2,3,7,8-positions in dibenzodioxine (DD ) are about ten times greater than those of the 1,4,6,9-positions. These HOMO coefficients are practically unaffected by halide substitution. But halogen substitution reduces strongly the electron density at the halogen-bound carbon, which, however, is a necessary prerequisite for the electrophilic oxygen transfer during metabolism. One would therefore expect halogen substitution of dibenzodioxine and dibenzofuran (DF) at the 2,3,7,8-position to hinder metabolism, as is indeed found. This provides a plausible explanation for the highly selective tissue retention of 2,3,7,8-substituted PCDDs and PCDFs. Our ab initio calculations of five tetra CDDs (T4CDDs) confirm the postulate of Kobayashi et al. [1 ] who, using semiempirical calculations, found a correlation between the toxicity of a dioxine congener and its absolute molecular hardness. The 2,3,7,8-T4CDD also exhibits the smallest absolute hardness (derived from the HOMO-LUMO energy gap) in our calculations.

Insight into the halogen-bond nature of noble gas-chlorine systems by molecular beam scattering experiments, ab initio calculations and charge displacement analysis

2019 ◽  
Vol 21 (14) ◽  
pp. 7330-7340 ◽  
Author(s):  
Francesca Nunzi ◽  
Diego Cesario ◽  
Leonardo Belpassi ◽  
Francesco Tarantelli ◽  
Luiz F. Roncaratti ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Molecular Beam ◽  
Halogen Bond ◽  
Noble Gas ◽  
Molecular Beam Scattering ◽  
Beam Scattering ◽  
Charge Displacement ◽  
Insight Into

A weak halogen bond, together with charge transfer from a noble gas to Cl2, characterizes the intermolecular interaction between a noble gas atom and Cl2 in a collinear configuration.

Some ab Initio Calculations on Indole, Isoindole, Benzofuran, and Isobenzofuran

1974 ◽  
Vol 29 (4) ◽  
pp. 624-632 ◽  
Author(s):  
J. Koller ◽  
A. Ažman ◽  
N. Trinajstić
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Chemical Shifts ◽  
Dipole Moments ◽  
Molecular Properties ◽  
Ionization Potentials ◽  
Charge Densities ◽  
Homo Lumo

Ab initio calculations in the framework of the methodology of Pople et al. have been performed on indole, isoindole, benzofuran. and isobenzofuran. Several molecular properties (dipole moments, n. m. r. chemical shifts, stabilities, and reactivities) correlate well with calculated indices (charge densities, HOMO-LUMO separation). The calculations failed to give magnitudes of first ionization potentials, although the correct trends are reproduced, i. e. giving higher values to more stable isomers. Some of the obtained results (charge densities, dipole moments) parallel CNDO/2 values.

Molecular structure, Vibrational assignment, HOMO-LUMO and Mulliken analysis of 2-[4-amino-2-(4-methylphenylamino) thiazol-5-oyl]benzothiazole(AMPATOB)

2016 ◽  
Vol 2 (1) ◽  
pp. 38
Author(s):  
Dr A Yardily
Keyword(s):  
Molecular Structure ◽  
Mass Spectra ◽  
Density Functional ◽  
Dft Method ◽  
Dihedral Angles ◽  
Atomic Charges ◽  
Vibrational Assignment ◽  
Functional Theory ◽  
Wave Numbers ◽  
Homo Lumo

The compound 2-[4-amino-2-(4-methylphenylamino) thiazol-5-oyl]benzothiazole (AMPATOB) was prepared from 1-(4-methylphenyl)-3-(N-nitroamidino)thiourea and 2-(2-bromoacetyl)benzothiazole in the presence of triethylamine and characterised  by FTIR, NMR and mass spectra. The geometry of the molecule was investigated and optimized with the help of B3LYP/ 6-31G density functional theory (DFT) method using Gaussian 09 software package.The calculated geometries such as bond lengths, bond angles, dihedral angles, atomic charges, harmonic vibrational wave numbers and intensities of vibrational bonds of the titled compound were investigated. The experimental 1H NMR and IR spectrum was compared with theoretical value. The molecule consists of three ring systems, all are lying in one plane.

Ultrafast Charge Transfer Studied by Femtosecond IR-Spectroscopy and ab Initio Calculations

2000 ◽  
Vol 47 (4A) ◽  
pp. 721-728 ◽  
Author(s):  
Andreas Kummrow ◽  
Jens Dreyer ◽  
Christian Chudoba ◽  
Jens Stenger ◽  
Erik Theodorus ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Ir Spectroscopy ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Ultrafast Charge Transfer

Fast approximation of the first-order intermolecular interaction energy: ab initio calculations using biorthogonal orbitals

2001 ◽  
Vol 547 (1-3) ◽  
pp. 209-217 ◽  
Author(s):  
Thierry Visentin ◽  
Christine Cézard ◽  
Gaétan Weck ◽  
Elise Kochanski ◽  
Lilyane Padel
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Interaction Energy ◽  
Intermolecular Interaction ◽  
Intermolecular Interaction Energy ◽  
First Order

An extended DFTB-CI model for charge-transfer excited states in cationic molecular clusters: model studies versus ab initio calculations in small PAH clusters

2016 ◽  
Vol 18 (5) ◽  
pp. 3545-3557 ◽  
Author(s):  
Léo Dontot ◽  
Nicolas Suaud ◽  
Mathias Rapacioli ◽  
Fernand Spiegelman
Keyword(s):  
Charge Transfer ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Excited States ◽  
Configuration Interaction ◽  
Density Functional ◽  
Tight Binding ◽  
Molecular Clusters ◽  
Molecular Cluster ◽  
Model Studies

We present an extension of the constrained density functional tight binding scheme combined with configuration interaction (DFTB-CI) to efficiently compute excited states of molecular cluster cations.

Intermolecular Potential Function Including Anisotropie Terms for Ammonia/Cu2+ Based on ab-initio Calculations

1990 ◽  
Vol 45 (11-12) ◽  
pp. 1303-1308
Author(s):  
R. T. Kroemer ◽  
Y. Michopoulos ◽  
B. M. Rode
Keyword(s):  
Charge Transfer ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Potential Function ◽  
Pair Potential ◽  
Basis Set ◽  
Intermolecular Potential ◽  
Transfer Effects

AbstractAn intermolecular pair potential function for Cu2+-NH3 has been derived based on ab-initio calculations with a ECP-DZV basis set. For copper the original ECP-DZV basis set was modified in order to avoid unwanted charge-transfer effects. The final potential function including anisotropic terms was constructed from a total of 679 configurations.

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