The non-classical KP(6)Mo(18)O(73) heteropolyanion has been studied by the density functional theory (DFT) method, and the calculated geometry compares well with the experimental one. In fully oxidized [KP(6)Mo(18)O(73)](7-) state, the d(xy)-orbitals centered at eight "belt" Mo sites in the lower part of the "basket" are the major contributors to the LUMO and LUMO+1, while the LUMO+2 orbital is...

Detailed simulations are reported for the dynamics of electrons and nuclei during the cis to trans photoisomerization of stilbene. Our method, which employs a semiclassical description of both the nuclear motion and the radiation field, is described in the text. After excitation of electrons from the highest occupied molecular orbital ~HOMO! to the lowest unoccupied molecular orbital ~LUMO! by ...

Results of classical force field geometry optimizations for twisted graphene nanoribbons with a number of twists N(t) varying from 0 to 7 (the case N(t)=1 corresponds to a half-twist Möbius nanoribbon) are presented in this work. Their structural stability was investigated using the Brenner reactive force field. The best classical molecular geometries were used as input for semiempirical calcul...

Quantum mechanical calculations have been carried out to determine the structural and electronic properties of the electron donor-acceptor complexes of C60 and C70 with azulene and some of its derivative, viz, 1,3-dichloroazulene, 2-hydroxyazulene and 4,6,8-trimetrhyl azulene. The molecules studied are optimized first with semi-empirical molecular orbital theory at the third parametric level, a...

This article reports the design and synthesis of donor-substituted symmetrical and unsymmetrical benzothiadiazoles (BTDs) of 5-12 type D-π-A-D, D1-π-A-D2, D1-A1-A2-D2, D-A1-A2-D and D-A1-A2-A1-D by Ullmann, Suzuki and cycloaddition-retroelectrocyclization reactions. The photophysical, electrochemical and computational properties were studied and show substantial donor-acceptor interaction. Thei...

We describe the design and synthesis of a new graphene ribbon architecture that consists of perylenediimide (PDI) subunits fused together by ethylene bridges. We created a prototype series of oligomers consisting of the dimer, trimer, and tetramer. The steric congestion at the fusion point between the PDI units creates helical junctions, and longer oligomers form helical ribbons. Thin films of ...

This paper reports the synthesis, characterization, photophysical and structural properties of the homologous series of good emitting pentacoordinated GaQ'2L complexes 1-3, where Q' is 2-methyl-quinolin-8-olate and L is a phenolate substituted in para position with respect to the oxygen donor atom. A combined approach between the experimental structural analysis (i.e. the molecular fragments in...

We use time-dependent density functional theory and time-dependent ZINDO (a semi-empirical method) to study transfer of an extra electron between a pair of pentacene molecules. A measure of the electronic transfer integral is computed in a dynamic picture via the vertical excitation energy from a delocalized anionic ground state. With increasing dimer separation, this dynamical measurement of c...

the density functional theory (dft) and the natural bond orbital (nbo) calculations basedmethod b3lyp/6-31g* were carried out to study the interaction of carbon nanotube (8,0) withnitrobenzene in two situations perpendicular and parallel. formation energies of compounds,charges, the highest occupied molecular orbital (homo) and the lowest unoccupied molecular'orbital (lumo) and the homo-lumo ba...

Bacteriochlorophylls (BChls) play an important role as light harvesters in photosynthetic bacteria. Interestingly, bacteriochlorophylls (BChls) a, b, and g selectively tune their visible (Qx) and near IR (Qy) absorption bands by the substituent changes. In this paper, we theoretically study the mechanism for the selective control of the absorption bands. Density functional theory (DFT) and time...