Residual Coulomb interaction fluctuations in chaotic systems: the boundary, random plane waves, and semiclassical theory

New fluctuation properties arise in problems where both spatial integration and energy summation are necessary ingredients. The quintessential example is given by the short-range approximation to the first order ground state contribution of the residual Coulomb interaction. The dominant features come from the region near the boundary where there is an interplay between Friedel oscillations and fluctuations in the eigenstates. Quite naturally, the fluctuation scale is significantly enhanced for Neumann boundary conditions as compared to Dirichlet. Elements missing from random plane wave modeling of chaotic eigenstates lead surprisingly to significant errors, which can be corrected within a purely semiclassical approach.     

Quantum group invariant integrable n-state models with periodic boundary conditions

Using the methods of topological quantum field theory we construct aU _q [sl(n)] invariant integrable transfer matrix for the case ofq being a root of unity. It corresponds to a 2-dimensional vertex model on a torus with topological interaction w.r.t. its interior. By means of the nested Bethe ansatz method we analyse conformai properties and discuss the representational content of the Bethe ansatz solutions.     

Excited state properties of transition metal phosphine complexes

Phosphine ligands determine the excited state properties of a variety of coordination compounds. Phosphines not only influence metal-centered excited states, but participate directly in charge transfer transitions owing to their electron donating and accepting ability. Moreover, intraligand excited states are accessible if the phosphine carries suitable substituents. This diversity is illustrated by selected examples. The excited state behavior is discussed on the basis of spectral (absorption and emission) and photochemical properties of appropriate phosphine complexes.     

Photoluminescence of osmocene and decamethylosmocene

Osmocene (and decamethylosmocene) is characterized by a lowest-energy ligand field triplet which occurs at _max=372nm (374nm) in absorption and 567nm (572nm) in emission. This orange–yellow phosphorescence is rather intense at 77K but is also visible at r.t.     

Boronate-based fluorescent probes for imaging cellular hydrogen peroxide

The syntheses, properties, and biological applications of the Peroxysensor family, a new class of fluorescent probes for hydrogen peroxide, are presented. These reagents utilize a boronate deprotection mechanism to provide high selectivity and optical dynamic range for detecting H2O2 in aqueous solution over similar reactive oxygen species (ROS) including superoxide, nitric oxide, tert-butyl hydroperoxide, hypochlorite, singlet oxygen, ozone, and hydroxyl radical. Peroxyresorufin-1 (PR1), Peroxyfluor-1 (PF1), and Peroxyxanthone-1 (PX1) are first-generation probes that respond to H2O2 by an increase in red, green, and blue fluorescence, respectively. The boronate dyes are cell-permeable and can detect micromolar changes in H2O2 concentrations in living cells, including hippocampal neurons, using confocal microscopy and two-photon microscopy. The unique combination of ROS selectivity, membrane permeability, and a range of available excitation/emission colors establishes the potential value of PR1, PF1, PX1, and related probes for interrogating the physiology and pathology of cellular H2O2.