The capability of the exciton scattering approach, an efficient methodology for excited states in branched conjugated molecules, is extended to include symmetric triple and quadruple joints that connect linear segments on the basis of the phenylacetylene backbone. The obtained scattering matrices that characterize these vertices are used in application of our approach to several test structures...

Ž . Ž . We use inverse photoelectron spectroscopy IPES and ultraviolet photoelectron spectroscopy UPS to investigate Ž . unoccupied and occupied electronic states of five organic semiconductor materials: CuPc copper phthalocyanine , PTCDA Ž . Ž . Ž X X Ž . X 3,4,9,10-perylenetetracarboxylic dianhydride , a-6T a-sexithiophene , a-NPD N,N -diphenyl-N,N -bis l-naphthyl -l,l XX . Ž Ž . . biphenyl-4...

The random phase approximation combined with semiempirical Hamiltonians is applied to compute and analyze electronic structure and excited state adiabatic potentials of several conjugated molecules. Calculated excited state energies and parameters of molecular adiabatic surfaces characterize the coupled dynamics of vibrational and electronic degrees of freedom. The analysis identifies the speci...

We have studied the properties of singlet open-shell molecules that are designed, synthesized, and isolated by us. The molecules contain p-quinodimethane or cumulene structures in the middle of their skeletons, and also equip spindelocalizing moieties, phenalenyl, in the both ends for thermodynamic stabilization. Crystal structures and electronic spectra revealed that these conjugated Kekulé mo...

Conjugated polymers have enormous potential as novel electronic materials that combine the electrical properties of semiconductors with the good mechanical strength and processing advantages of plastics. [ 1 , 2 ] Perhaps nowhere is this more evident than in the synthesis of conjugated heterocyclic polymers based on thiophene units or monomers. [ 3 ] Owing to their facile preparation, relativel...

The transparency of contacts between conjugated molecules and metallic single-walled carbon nanotubes is investigated using a single-particle Green's function method which combines a Landauer approach with ab initio density functional theory. We find that the overall conjugation required for good contact transparency is broken by connecting through a six-member ring on the tube. Full conjugatio...

The Randić index R(G) of a graph G is the sum of the weights (d(u)d(v))− 1 2 of all edges uv of G, where d(u) denotes the degree of the vertex u. In this paper, we first present a sharp lower bound on the Randić index of conjugated unicyclic graphs (unicyclic graphs with perfect matching). Also a sharp lower bound on the Randić index of unicyclic graphs is given in terms of the order and given ...