The density functional calculation with the generalized gradient approximation is applied to study the structural, properties of AlnGan clusters up to n=12. At the same time the frequency was performed when the structure optimization in order to assure the calculated-ground states were real low-lying. The nearest-neighbor distance, total energy, electron affinities and HOMO-LUMO gap were presen...

We report the results of a theoretical study of sequential oxidation of gallium oxide clusters from Ga3O4 to Ga3O8. These results, based on density functional theory calculations, find the ground state of the neutral clusters to be in the lowest spin state with nearly the same binding energy of 3.5 eV per atom. Electron affinity, ionization potential and HOMO–LUMO gap values of these oxygen-ric...

The Dawson-type polyanion [α-Mo(18)O(54)(SO(3))(2)](4-), with two SO(3)(2-) templates embedded inside a polyoxomolybdate(vi) cage, exhibits thermochromism over an exceptionally wide temperature range (∼500 K). The temperature dependence of the cluster structure, established from X-ray crystallography, IR and Raman spectroscopy and DFT calculations, is related to a decreasing HOMO-LUMO gap in th...

Important parameters of an organic semiconductor material are the electronic band gap (Eg) and position highest occupied lowest unoccupied bands versus vacuum. These called valence conduction for inorganic semiconductors. For semiconductors defining often molecular orbital (HOMO) (LUMO). One advantage semiconducting polymers is ability to tune HOMO LUMO levels by chemical design. The photovolta...

A four-step route for the synthesis of 5-azatetracene (benzo[b]acridine) has been developed, employing a base-catalysed Friedlander condensation reaction between 3-amino-2-napthaldehyde and cyclohexanone as key step followed by dehydrogenation intermediate. The optical electrochemical properties were investigated UV-vis photoluminescence spectroscopy, cyclic voltammetry compared with those tetr...

We present an analysis of the temperature dependence of the optical response of small sodium clusters in a temperature range bracketing the melting phase transition. When the temperature increases, the mean excitation energy undergoes a red shift and the plasmon is significantly broadened, in agreement with recent experimental data. We show that the single–particle levels acquire a prominent wi...

If quantum interference patterns in the hearts of polycyclic aromatic hydrocarbons could be isolated and manipulated, then a significant step toward realizing the potential of single-molecule electronics would be achieved. Here we demonstrate experimentally and theoretically that a simple, parameter-free, analytic theory of interference patterns evaluated at the mid-point of the HOMO-LUMO gap (...

We report a facile synthesis of novel angularly fused bistetracene derivatives where two tetracene skeletons are cata-annulated at three benzene rings. Compared with previously described examples, our bistetracenes exhibit a narrower HOMO–LUMO gap but still exhibit high stability. Attempted synthesis of di-substituted bistetracene (BT-2TIPS) also led to unexpected triple (BT-3TIPS) and four-fol...

Representative atomic and molecular systems, including various inorganic and organic molecules with covalent and ionic bonds, have been studied by using density functional theory. The calculations were done with the commonly used exchange-correlation functional B3LYP followed by a comprehensive analysis of the calculated highest-occupied and lowest-unoccupied Kohn-Sham orbital (HOMO and LUMO) e...