Browsing by Subject "Quadrupole coupling constant"

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DFT explorations of quadrupole coupling constants for planar 5-fluorouracil pairs
(Elsevier, 2016-08) Mirzaei, M.; Gülseren, O.; Hadipour, N.
Atomic scale properties of quadrupole coupling constants (CQ) have been evaluated for singular and paired 5-fluorouracil (FU) models. Structural possibilities and properties for various types of hydrogen bonded (HB) homo pairs of FU have been investigated based on density functional theory (DFT) calculations. The models have been optimized to obtain the minimum energy level structures and only the planar molecular pairs have been considered. Various types of HB interactions have also managed the molecular shapes for the FU pairs. Different types of energies and also electron transferring properties have been investigated by the evaluated optimized properties. The atomic scale results indicated different strengths of HB interactions for FU pairs according to the changes of CQ properties for atoms in the singular and paired systems depending on the strength of interactions.
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Relaxations of methylpyridinone tautomers at the C60 surfaces: DFT studies
(Islamic Azad University, 2017) Naderi, E.; Mirzaei, M.; Saghaie, L.; Khodarahmi, G.; Gülseren, O.
Density functional theory (DFT) based calculations have been performed to examine the relaxations of tautomers of 4–hydroxy–6–methylpyridin–2(1H)–one (MPO), as a representative of pyridinone derivatives, at the fullerene (C60) surfaces. Optimized molecular properties including energies, dipole moments and atomic scale quadrupole coupling constants (CQ) have been evaluated to investigate the structural and electronic properties of the models. The structural configurations of tautomers show different relaxations at the C60 surface yielding different magnitudes of total and binding energies. Moreover, deformation of each tautomer due to relaxation at the C60 surface with respect to the initial singular structure has been examined. Complimentary parameters of energy gaps and dipole moments exhibit the effects of relaxations at the C60 surface for the MPO counterparts. Atomic scale CQ properties also indicate that the electronic properties of atoms show significant changes for tautomers and hybrid systems. As a final note, the tautomeric structures in singular and hybrid forms exhibit different electronic properties because of effects of interactions with C60, especially for the interaction regions.