The electronic structure and photophysical properties of (C=C)TTP(2+) (TTP = tetra-p-tolylporphyrin) were scrutinized by using quantum mechanical calculations and transient absorption spectroscopic measurements. When compared to a metalloporphyrin, the presence of the C=C unit in (C=C)TTP(2+) causes a splitting of the degenerate LUMO and a large decrease in the HOMO-LUMO gap, while the 2+ charg...

The research in the short-chain organic -conjugated molecules has become one of the most interesting topics in the fields of chemistry. These compounds have become the most promising materials for the optoelectronic device technology. The use of low band gap materials is a viable method for better harvesting of the solar spectrum and increasing its efficiency. The control of the band gap of th...

The aim of the present study was to prepare new cluster (B6C4Si) as an antibiotic carrier. Density functional theory (DFT) method at the B3LYP level of theory in conjugate with the 6-311G** basis set was used to evaluate the interaction between B6C4Si cluster and Penicillin. Binding parameters, HOMO, LUMO and HOMO- LUMO GAP were calculated. Results show the ‍ B6C4Si HOMO–LUMO gap value of 0.13...

Using an ab initio molecular-dynamics scheme ~the ‘‘fireball’’ scheme!, we determined the equilibrium structure of intermediate-size SinGem (n1m571) nanoclusters with and without hydrogen passivation on the surface. Due to the strong surface distortion, defect states are found to permeate the energy gap of SinGem clusters. However, the defect states are removed by adding H atoms on the surface ...

We study Ge2O2 and Ge2O2 2 with density functional theory ~DFT! and photoelectron spectroscopy ~PES!. We find that Ge2O2 is a rhombus ~D2h), closed-shell molecule with a large HOMO-LUMO gap. The PES spectrum of Ge2O2 2 is obtained at four detachment photon energies: 1064, 532, 355, and 266 nm. Vibrational structure is resolved at the lowest photon energy with a single progression and a frequenc...

A detailed study of energy differences between the highest occupied and lowest unoccupied molecular orbitals (HOMO-LUMO gaps) in protein systems and water clusters is presented. Recent work questioning the applicability of Kohn-Sham density-functional theory to proteins and large water clusters (Rudberg 2012 J. Phys.: Condens. Matter 24 072202) has demonstrated vanishing HOMO-LUMO gaps for thes...

Using photoelectron spectroscopy and first principles molecular orbital calculations, we report the first observation of an abrupt change in the electronic structure of W4O m (m6 6) clusters at m 1⁄4 5 which is well below the bulk stoichiometric composition of tungsten oxide (WO3). The signature of this onset is established from an anomalous increase in the vertical detachment energies (VDE), a...

The reactions of propenyl magnesium halides with ethylene were studied using ab initio calculations. The structure of the transition state and the ground state were evaluated and obtained the structural properties, theoretical thermodynamic and kinetic data i.e. rate constants of the reactions. The methods used for calculations are RHF, B3LYP and MP2 with 6-31G* b...

the density of state and the natural bond orbital calculations were carried out to study theoxidation of co on au14 nano cluster through two different mechanisms and determining the bestmechanism for the reaction. chemisorption of o2 and co on the nano cluster led to change in energy,density of state and its thermodynamic properties. we calculated the energy band gap between thehighest occupied...

Heteroleptic (CN)2Ir(acac) (C ∧N = 4-CBppy (1); 5-CBppy (2), 4-fppy (4) CB = ortho-methylcarborane; ppy = 2-phenylpyridinato-C,N, 4-f ppy = 2-(4-fluorophenyl)pyridinato-C,N, acac = acetylacetonate) complexes were prepared and characterized. While 1 exhibits a phosphorescence band centered at 531 nm, which is red-shifted compared to that of unsubstituted (ppy)2Ir(acac) (3) (λem = 516 nm), the em...