The Frenkel exciton Hamiltonian is at the heart of many simulations of excitation energy transfer in molecular aggregates. It separates the aggregate into Coulomb-coupled monomers. Here it is shown that the respective parameters, i.e., monomeric excitation energies and Coulomb couplings between transition densities can be efficiently calculated using time-dependent tight-binding-based density f...

Quantum chemistry calculations have been performed to compute the optimized geometries, vibrational frequencies, and Mulliken Charges at B3LYP/6-31G(d) and B3LYP/6-311++G(d,p) levels for 3-(4-fluorophenyl)thiophene (FPT), 3-(4-nitrophenyl)thiophene (NPT) and 3-(4-cyanophenyl) thiophene (CPT) in the ground state. In addition, the (13)C and (1)H NMR are calculated by B3LYP/6-311++G(d,p) and B3LYP...

7Recent work by H. A. Harbury and K. A. Foley (these PROCEEDINGS, 44, 662-665, 1958) shows that caffeine behaves similarly to tryptophan in giving up an electron when complexing with riboflavin. This gives good evidence of the electron-donor properties of this purine. ' R. S. Mulliken, J. Am. Chem. Soc., 72, 600-608, 1950; 811-820, 1952; J. Phys. Chem. 56, 801-822, 1952; Rec. Trav. C/rim., 75, ...

The intramolecular alpha-arylation of aldehydes via organo-SOMO catalysis was investigated using density functional theory (B3LYP and M06-2X functionals). The geometries, spin densities, Mulliken charges, and molecular orbitals of the reacting enamine radical cations were analyzed, and the nature of the resulting cyclized radical cation intermediates was characterized. In agreement with experim...

Density functional theory (UB3LYP/6-31G(d,p)) was used to determine substituent effects on the singlet-triplet-state energy gap for 21 meta-substituted phenylnitrenium ions. It was found that strongly electron-donating substituents stabilize the triplet state relative to the singlet state. With sufficiently strong meta electron donors (e.g., m,m'-diaminophenylnitrenium ion) the triplet is predi...

A gas sensor is used to detect SF6 decomposed gases, which are related to insulation faults, to accurately assess the insulated status of electrical equipment. Graphene films (GrF) modified with Au nanoparticles are used as an adsorbent for the detection of H2S and SOF2, which are two characteristic products of SF6 decomposed gases. Sensing experiments are conducted at room temperature. Results...

The protection influence of three sulfa guanidine azo derivatives against nickel corrosion was studied in 0.5 M HCl solutions at 25oC. Measurements were conducted under various experimental conditions using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) techniques. These studies have shown that sulfa guanidine azo deriva...

An electrochemical variational method (de la Rosa, et al. Inorg. Chem. 1985,24,4229) has been used to examine experimentally the extent of metal/ligand orbital mixing and electronic coupling in complexes of the type Ru"(NHJ4L2+ (L = 2,2'-bipyridine or 1 ,IO-phenanthroline). From the experiments, strong localization of d r electrons at the ruthenium metal center is indicated, Nevertheless, some ...

Potential crystal structures of BeB2 were explored using ab initio evolutionary simulations. A new phase with a Cmcm space group was uncovered. It was determined that the Cmcm phase is mechanically and dynamically stable and has a lower enthalpy, from ambient pressure up to 13 GPa, than any previously proposed phases, as measured using first-principles calculations. The crystal structure, phono...

Novel Schiff base (H(2)L, 1,2-bis[(2-(2-mercaptophenylimino)methyl)phenoxy] ethane) derived from condensation of bisaldehyde and 2-aminothiophenol was prepared in a molar ratio 1:2. The ligand and its metal complexes are fully characterized with analytical and spectroscopic techniques. The metal complexes with Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Th(IV) have been prepare...