Electronic and transport properties of Graphene, a one-atom thick crystalline material, are sensitive to the presence of atoms adsorbed on its surface. An ensemble of randomly positioned adatoms, each serving as a scattering center, leads to the Bolzmann-Drude diffusion of charge determining the resistivity of the material. An important question, however, is whether the distribution of adatoms ...

Five theoretical and/or experimental problems involving benzenoid polycyclics and related eystems are discussed. The dualiet graph characterizes uniquely any polycyclic aromatic hydrocarbon (PAH or pol.yhex), and differentiates between catafusenes, perifusenes and coronafusenes (catahexes, perihexes, coronahexes). 1. The topology of catafusenes, expre8sed by their dualist graphs, can be correla...

The analysis of π-electronic structure of polymer networks continues to attract the interest of theoretical1 and synthetic2-7 researchers. One of the major objectives of these studies is to gain insight on the design of potential organic conductors and ferromagnets. Extended pπ-conjugated systems represent the simplest models for molecular wires. The reduction of the HOMO-LUMO bandgap in conjug...

Carbocations are traditionally thought to be closed-shell electrophiles featuring an empty orbital rich in p character. Here, density functional theory computations indicate that when strong π donors are not placed in direct conjugation with benzylic-type cations, alternative diradical configurations that resemble non-Kekulé diradicals are possible. For certain donor-acceptor frameworks, an ope...