High resolution laser induced fluorescence excitation spectroscopy of jet-cooled terrylene

High resolution laser induced fluorescence excitation spectra upon absorption in the A¹B_3u ← X¹A_g band of jet-cooled terrylene have been recorded. Precise energies of three vibronic transitions are deduced. Low lying vibrations are found in both electronic states. Rotational constants in ground and excited state are determined by band contour analysis. Terrylene is a medium-size polycyclic aromatic hydrocarbon (PAH) and a possible carrier of diffuse interstellar bands (DIB). The results of the jet experiments are discussed regarding the PAH-DIB hypothesis.     

Convergence of continuous linear functionals and their level sets

Archiv der Mathematik -     

A Soluble Donor–Acceptor Double-Cable Polymer: Polythiophene with Pendant Fullerenes

Summary.  We report the synthesis and the spectroscopic properties of a novel soluble thiophene-based copolymer carrying pendant fullerene moieties (donor–acceptor double-cable polymer). Photoinduced absorption (PIA) experiments on spin cast films reveal a photoinduced electron transfer from the polythiophene chain onto the fullerene moieties. The performance of photovoltaic devices produced with this copolymer is also discussed. Corresponding author. E-mail: antonio.cravino@jku.at Received August 16, 2002; accepted (revised) August 26, 2002     

Recombination Measurements at Ion Storage Rings

Hyperfine Interactions - An overview of recombination measurements is given, focusing on experiments with multicharged ions and electrons at relative energies in the millielectronvolt range....     

Letters to the editor

The mathematical intelligencer encourages comments about the material in this issue. letters to the editor should be sent to the editor-in-chief, chandler davis.     

An Integral Simplex Algorithm for Solving Combinatorial Optimization Problems

In this paper a local integral simplex algorithm will be described which, starting with the initial tableau of a set partitioning problem, makes pivots using the pivot on one rule until no more such pivots are possible because a local optimum has been found. If the local optimum is also a global optimum the process stops. Otherwise, a global integral simplex algorithm creates and solves the problems in a search tree consisting of a polynomial number of subproblems, subproblems of subproblems, etc. The solution to at least one of these subproblems is guaranteed to be an optimal solution to the original problem. If that solution has a bounded objective then it is an optimal set partitioning solution of the original problem, but if it has an unbounded objective then the original problem has no feasible solution. It will be shown that the total number of pivots required for the global integral simplex method to solve a set partitioning problem having m rows, where m is an arbitrary but fixed positive integer, is bounded by a polynomial function of n.A method for programming the algorithms in this paper to run on parallel computers is discussed briefly.     

A convenient synthesis of 2-substituted 4-amino-5-pyrimidinecarbonitriles

Synthesis of the novel 2-halogenated 4-amino-5-pyrimidinecarbonitriles 3a,b starting from ethoxy-methylenemalononitrile 1 and cyanamide is described. Nucleophilic substitution of the reactive halogen atom leads to the derivatives 5a-g, 6 and 7a-h.