We use fluorescence from dye-labelled polymer to measure the glass transition temperatures (Tgs) across single-layer films and near surfaces and silica interfaces in bilayer films for a series of poly(n-methacrylate)s. With nanoscale confinement, the average Tg across a film supported on silica increases for poly(methyl methacrylate) (PMMA), decreases for poly(ethyl methacrylate) (PEMA) and poly(propyl methacrylate), and is nearly invariant for poly(iso-butyl methacrylate) (PIBMA). These trends are consistent with the relative strengths of local perturbations to Tg caused by surfaces and substrates as measured in bilayer films. The substrate effect, which increases Tg via hydrogen-bonding interactions between the polymer and hydroxyl groups on the silica surface, is stronger than the free-surface effect in PMMA. The free-surface effect, which reduces Tg via a reduction in the required cooperativity of the glass transition dynamics, is stronger than the substrate effect in PEMA. The substrate and free-surface effects have similar strengths in perturbing the local Tg in PIBMA, resulting in a net cancellation of effects when measurements are made across single-layer films.

For the reaction M(+)(C(2)H(4))(n-1) + C(2)H(4) --> M(+)(C(2)H(4))(n), where M = Ag, Au, the binding energies are predicted at the second order perturbation (MP2) and coupled cluster (CCSD(T)) levels of theory. As the basis set is systematically improved, the predicted M = Ag binding energies steadily improve, as compared to the experimental values. In fact, the complete basis set limit (CBS) predicted CCSD(T) binding energy for Ag(C(2)H(4))(+) is within experimental error. For MP2, as the basis set is improved, the agreement with experiment worsens. Gold ions are predicted to bind more strongly than silver ions to ethene ligands. Mulliken population analyses of the silver and gold systems exhibit delocalization of the positive charges of the metal ions onto the ethene ligands. Reduced variational space analysis indicates that electrostatic interactions are the principal contributor to the bonding in these systems. Multiconfigurational self-consistent field calculations do not support the Dewar-Chatt-Duncanson model of transition metal-alkene bonding in Au(C(2)H(4))(+).