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...

in this work, the optimization calculations were carried out on quetiapine hemifumarat, 4, and its analogues, 1-5. these calculations were carried out using the b3lyp/6-31g(d) level of theory. the dft calculations clarified a boat structure for dibenzothiazepine moiety of the molecule which piperazine moiety has a chair conformation. thermal energies (e), enthalpies (h), and free energies (g) o...

in the present work, the structural and electronic properties, and conductivity of (5,5) and (6,6) single walled carbon nanotubes in the ground state have done by using the hartree-fock and density functional theory dft-b3lyp/6-31g* level. delocalization of charge density between the bonding or lone pair and antibonding orbitals calculated by nbo (natural bond orbital) analysis. these methods a...

in the present work, the quantum theoretical calculations of the molecular structure of the 1-(1, 3-benzothiazol-2-yl)-3-(thiophene-5-carbonyl) thiourea has been predicted and are evaluated using density functional theory (dft) in gas phase. the geometry of the title compound was optimized by b3lyp/6-311+g and b3lyp/6-311+g* methods and the experimental geometrical parameters of the title compo...

in this study we investigate the effect of atoms such as b, n, ge and sn on the optical and the electrical properties of capped (5, 0) zigzag carbon nanotube, using dft calculation method. these elements were attached to the one end of the carbon nanotube. we considered four different structure designs as possible candidates for a p-n junction device. the electrical properties of these structur...

We present a new method for estimating the vibrational free energy of crystal (and molecular) structures employing only a single force calculation, for a particularly displaced configuration, in addition to the calculation of the ground state configuration. This displacement vector is the sum of the phonon eigenvectors obtained from a fast-relative to, e.g., density-functional theory (DFT)-Hess...

Recently, we introduced a new density-functional theory ~DFT! approach for the calculation of NMR shielding constants. First, a hybrid DFT calculation ~using 5% exact exchange! is performed on the molecule to determine Kohn–Sham orbitals and their energies; second, the constants are determined as in nonhybrid DFT theory, that is, the paramagnetic contribution to the constants is calculated from...

We compare the performance of four recently developed DFT methods (MPW1B95, MPWB1K, PW6B95, and PWB6K) and two previous, generally successful DFT methods (B3LYP and B97-1) for the calculation of stacking interactions in six nucleic acid bases complexes and five amino acid pairs and for the calculation of hydrogen bonding interactions in two Watson-Crick type base pairs. We found that the four n...

We compare the performance of four recently developed DFT methods (MPW1B95, MPWB1K, PW6B95, and PWB6K) and two previous, generally successful DFT methods (B3LYP and B97-1) for the calculation of stacking interactions in six nucleic acid bases complexes and five amino acid pairs and for the calculation of hydrogen bonding interactions in two Watson– Crick type base pairs. We found that the four ...