We present and discuss measurements of electron-irradiation damage in polystyrene and other polymers, based on fading of the 7-eV energy-loss peak. These measurements suggest a large increase in characteristic dose as the electron-beam diameter is reduced from 1 μm to below 1 nm. This finding is discussed in terms of secondary-electron production and delocalization of the inelastic scattering, ...

Ab initio molecular dynamics simulations modeling low-energy collisions of a sodium atom with a cluster with more than 30 water molecules are presented. We follow the dynamics of the atom-cluster interaction and the delocalization of the valence electron of sodium together with the changes in the electron binding energy. This electron tends to be shared by the nascent sodium cation and the wate...

Quantum-chemical calculations were performed for all possible nine neutral tautomers of purine and their oxidized and reduced forms in water {PCM//DFT(B3LYP)/6-311+G(d,p)} and compared to those in the gas phase {DFT(B3LYP)/6-311+G(d,p)}. PCM hydration influences geometries, π-electron delocalization, and relative energies of purine tautomers in different ways. Generally, the harmonic oscillator...

Standard rate constants (k,) for interfacial electron transfer (ET) have been obtained for several redox couples featuring very small internal activation barriers. To render these ordinarily fast rates more easily measurable, we have employed low-defect-density, highly ordered pyrolytic graphite (HOPG) as an electrode material (see: Allred and McCreery, Anal. Chem. 1992,64,444). At the HOPG/aqu...

A method is introduced for simple calculation of charge transfer between very large solvated organic dimers (fullerenes here) from isolated dimer calculations. The individual monomers in noncentrosymmetric dimers experience different chemical environments, so that the dimers do not necessarily represent bulk-like molecules. Therefore, we apply a delocalizing bias directly to the Fock matrix of ...

Single-molecule study of phenylenevinylene oligomers revealed distinct spectral forms due to different conjugation lengths which are determined by torsional defects. Large spectral jumps between different spectral forms were ascribed to torsional flips of a single phenylene ring. These spectral changes reflect the dynamic nature of electron delocalization in oligophenylenevinylenes and enable e...

Interfacial electron transfer dynamics of a series of photosensitizers bound to TiO2via linkers of varying conjugation strength are explored by spectroscopic and computational techniques. Injection and recombination depend on the extent of conjugation in the linker, where the LUMO delocalization determines the injection dynamics but both the HOMO and HOMO-1 are involved in recombination.