The nonlinear optical properties of new tetrathiafulvalenes and 1,3-dithioles have been studied using first principle methods. The higher hyperpolarizabilities of the extended 1,3-dithioles compared to Tetrathiafulvalene analogs are explained on the basis of the less localized HOMO of the former giving rise to higher transition dipole moments and a more pronounced decrease of the HOMO-LUMO gap ...

The influence of the insertion/addition of a benzene ring to the natural nucleic acid bases on the local aromaticity of the so-called size-expanded (xN, with N being adenine, guanine, cytosine, and thymine) bases is examined. To this end, the local aromaticity of the six- and five-membered rings in both the natural bases and their benzoderivatives is determined using HOMA, NICS, aromatic fluctu...

For analyzing of compositions molecular orbitals in this article in order to combination only- xylometazolin-C7 X2 (XY) and C60– xylometozolin-C65-X2 (FXY), first got energies of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) by using NBO analyze in Gaussian 03 software. Then, occupancy parameter, g...

Studies using ultraviolet photoelectron spectroscopy (UPS) and density functional theory (DFT) demonstrate that M4X6 (M = W, Mo and X = O, S) clusters show large gaps (about 2 eV) between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), indicative of their high stability and chemical inertness. In particular, W4O6 has a lower symmetry and a large...

For analyzing of compositions molecular orbitals in this article in order to combination only- xylometazolin-C7 X2 (XY) and C60– xylometozolin-C65-X2 (FXY), first got energies of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) by using NBO analyze in Gaussian 03 software. Then, occupancy parameter, g...

The extended SSH model and Bogoliubov-de Gennes(BdeG) formalism are applied to investigate the electronic properties and stable lattice configurations of C36. We focus the problem on the molecule’s unusual D6h symmetry. The electronic part of the Hamiltonian without Coulomb interaction is solved analytically. We find that the gap between HOMO and LUMO is small due to the long distance hopping b...

The derivative discontinuity of the exchange-correlation functional of density-functional theory is cast as the difference of two types of electron affinities. We approximately evaluate this difference via ordinary Kohn-Sham calculations, obtaining estimates of the discontinuity for light atoms and for polyacetylene oligomers. The discontinuity is found to be quite large (typically several eV),...

the present work reports the detailed b3lyp/6-311++g(d,p) study of most stable transand cisconfigurations photoisomerization in the core system of computational photochemistry-the 5,5'-disubstituted-1,1'-azobis (tetrazole) molecules. all computations were carried out in gas phase attemperature 293.15 k and pressure 1 atm. firstly; the potential energy surface (pes) of the groundstate ...

Abstract: Electrical sensitivity of a boron nitride nanotube (BNNT) was examined toward (C3H4) molecule by using density functional theory (DFT) calculations at the B3LYP/6-31G (d) level, and it was found that the adsorption energy (Ead) of methylacetylene (C3H4) the pristine nanotubes is a bout -1.78kcal/mol. But when nanotube have been doped with Si and Al atomes, the adsorption energy of me...

Abstract: Electrical sensitivity of a boron nitride nanotube (BNNT) was examined toward pyrrole (C5H6N) molecule by using density functional theory (DFT) calculations at the B3LYP/6-31G (d) level, and it was found that the adsorption energy (Ead) of pyrrole on the pristine nanotubes is a bout -16.37kcal/mol. But when nanotube have been doped with Si and Al atom...