نتایج جستجو برای: quantum theory of atoms in molecules qtaim

تعداد نتایج: 24511444  

Journal: :Molecules 2016
Maria Kasprzak Małgorzata Fabijańska Lilianna Chęcińska Leszek Szmigiero Justyn Ochocki

This work presents the synthesis, spectroscopic properties and single-crystal X-ray examination of the structure of 3-hydroxyiminoflavanone and its palladium complex. It presents the results of NMR (Nuclear Magnetic Resonance) spectroscopy, electron-density studies based on X-ray wavefunction refinement and theoretical calculations combined with QTAIM (Quantum Theory of Atoms in Molecules) and ...

Journal: :Molecular Simulation 2023

In this work, we have studied the microsolvation of phenol in water. We started by identifying initial configurations phenol-water clusters using classical molecular dynamics. The are optimised at ωB97XD/aug-cc-pVDZ level theory. To understand interaction between and solvating water molecules, performed a quantum theory atoms molecules (QTAIM) analysis. results show that structures similar to t...

Journal: :Physical chemistry chemical physics : PCCP 2015
Zahra Badri Cina Foroutan-Nejad Jiri Kozelka Radek Marek

In the present work the nature of lone-pair-π interactions between water molecules and a number of π-rings with different substituents/hetero-atoms in the light of quantum chemical topology approaches is studied. The Quantum Theory of Atoms in Molecules (QTAIM) and Interacting Quantum Atoms (IQA) were employed for distinguishing the role of heteroatoms and electron withdrawing substituents in t...

Journal: :journal of physical & theoretical chemistry 2011
m. monajjemi a. eghdami

over the past decade, the chemical behavior of flavonoids as antioxidants has become the subject ofintense experimental research. in this paper, we use a quantum-chemical approach to shed light on thereactivity of four poly phenols, benzoic acid, vanilic acid, gallic acid and flavone . in order to establishthe most efficient theoretical methodology, different methods, either hartree—fock-based ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه لرستان - دانشکده علوم پایه 1389

abstract part one: the electrode oxidation potentials of a series of eighteen n-hydroxy compounds in aqueous solution were calculated based on a proper thermodynamic cycle. the dft method at the level of b3lyp-6-31g(d,p) was used to calculate the gas-phase free energy differences ,and the polarizable continuum model (pcm) was applied to describe the solvent and its interaction with n-hydroxy ...

2012
Agata Martyniak Pawel Lipkowski Noel Boens Aleksander Filarowski

The ketoenamine-enolimine tautometic equilibrium has been studied by the analysis of aromaticity and electron-topological parameters. The influence of substituents on the energy of the transition state and of the tautomeric forms has been investigated for different positions of chelate chain. The quantum theory of atoms in molecules method (QTAIM) has been applied to study changes in the electr...

Journal: :Molecules 2017
Gabriel J Buralli Andre N Petelski Nélida M Peruchena Gladis L Sosa Darío J R Duarte

In the present work an in depth deep electronic study of multicenter XBs (FX)n/NH₃ (X = Cl, Br and n = 1-5) is conducted. The ways in which X∙∙∙X lateral contacts affect the electrostatic or covalent nature of the X∙∙∙N interactions are explored at the CCSD(T)/aug-cc-pVTZ level and in the framework of the quantum theory of atoms in molecules (QTAIM). Calculations show that relatively strong XBs...

پایان نامه :وزارت علوم، تحقیقات و فناوری - پژوهشگاه دانشهای بنیادی (مرکز تحقیقات فیزیک نظری و - پژوهشکده علوم نانو 1392

among the low–dimensional allotropes of carbon, nanotubes and graphene have attracted very much attention from nano–science and nanotechnology specialists. they have been proposed as building blocks in nanometer device engineering. however, these structures are not defect–free. in this thesis, we focused on defective carbon nanotubes and graphene, and studied the effect of couple of very common...

Jamshid Najafpour, Narges Zohari

FOX-7 (1,1-diamino-2,2-dinitroethylene) recently is expected as a relatively new energetic material with high-performance and low sensitivity. The RHF and MP2 levels and DFT method with B3LYP functional with aug-cc-pVDZ basis set have been used for obtaining equilibrium geometry and Rho function (electron density distribution). By the aid of fundamental physical theorems implemented in the ...

Journal: :International Journal of Molecular Sciences 2023

In this work, intra- and intermolecular halogen chalcogen bonds (HlgBs ChBs, respectively) present in the solid state of nucleic acids (NAs) have been studied at RI-MP2/def2-TZVP level theory. To achieve this, a Protein Data Bank (PDB) survey was carried out, revealing series structures which Br/I or S/Se/Te atoms belonging to nucleobases pentose rings were involved noncovalent interactions (NC...

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