نتایج جستجو برای: density functional theory

تعداد نتایج: 1657734  

Journal: :physical chemistry research 2016
mohammad izadyar ramesh kheirabadi

antioxidants are made for the struggle and reconstruction of the damaged cells, because of their ability in destroying the free radicals. on account of their importance, a theoretical procedure was applied for the study of the molecular structure and radical scavenging activity of six hydroxyphenols which have been introduced as antioxidant compounds. all geometry structures were optimized by m...

Journal: :international journal of bio-inorganic hybrid nanomaterials 0

stabilities and quantum molecular descriptors of cyclophoshphamide (an anticancer drug)-functionalized (8,0) zigzag and (4,4) armchair carbon nanotubes (cnts) complexes in water were studied using density functional theory (dft) calculations. two attachments namely the sidewall- and tip-attachments are considered for the model constructions. calculations of the total electronic energy (et) and ...

Journal: :physical chemistry research 0
tayebeh hosseinnejad department of chemistry, faculty of science, alzahra university, vanak, tehran, iran

the main purpose of this research is to investigate computationally the tautomeric reaction pathway of 5-methyl-3-methylthio-1,2,4-triazole from the thermodynamical and mechanistical viewpoints. in this respect, density functional theory (dft) in conjunction with the quantum theory of atoms in molecule (qtaim) has been employed to model the energetic and electronic features of tautomeric mechan...

2011
Evert Jan Baerends O. V. Gritsenko K. J. H. Giesbertz Paul Ayers

Coupled cluster methods are considered among the most accurate tools in electronic structure theory. Nonetheless relatively limited attempt seems to have been made to extend their applicability to the description of the core-excitation phenomena that are behind largely used spectroscopic techniques like x-ray absorption spectroscopy and x-ray circular dichroism. As a first step to redeem for su...

Mahmoud Mirzaei

The electronic and structural properties of pristine and carbon doped (C-doped) boron nitride nano-ribbons(BNNRs) have been studied employing density functional theory (DFT) calculations. Total energies, gapenergies, dipole moments, and quadrupole coupling constants (qcc) have been calculated in the optimizedstructures of the investigated BNNRs. The results indicated that the stability and gap ...

Journal: :Physical review 2021

This work presents a theory to unify the two independent theoretical frameworks of Kohn-Sham (KS) density functional (DFT) and reduced matrix (RDMFT). The generalization KS orbitals hypercomplex number systems leads (HCKS) theory, which extends search space for in KS-DFT that is equivalent natural spin with fractional occupations RDMFT. Thereby, HCKS able capture multi-reference nature strong c...

H. Aghaie M. Aghaie M.H. Ghorbani

The molecular structure of the stable conformation of phosphonic acid in gas phase has beencomputed by employing complete geometry optimization in Density Functional Theory(DFT) methods. The methods used for calculations are B3LYP, BP86 and B3PW91 that havebeen studied in two series of basis sets: D95** and 6-31+G(d,p) for hydrogen and oxygenatoms; LANL2DZ for phosphorus. Bond lengths and angle...

Journal: :iranian journal of science and technology (sciences) 2012
m. jafari

in the present work, the electronic properties of titanium were studied in three phases of α, β and ω using the density function theory (dft). the full potential augmented plane wave plus local orbital (flapw+lo) method was applied using the generalized gradient approximation. the calculated total energies showed that omega phase was more stable than the two other phases. the largest electrical...

2006
Nikos L. Doltsinis

c 2006 by John von Neumann Institute for Computing Permission to make digital or hard copies of portions of this work for personal or classroom use is granted provided that the copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise requires prior specific permission by the publisher mentio...

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