Chain-structure-superstructure relations in eutectoid copolymers

It will be shown that low-density polyethylene is a eutectoid copolymer with non-random distribution of branchings along the chains. From a line-profile analysis it is deduced that the crystal-size-distribution is uniquely related with the distribution of branchings thus yielding that basic features of the colloid-structure are controlled by the chemical structure of the macromolecules.     

Birefringence of stretched polyethylene and its relation to changes in structure

It is shown that the birefringence of a polyethylene crystal can be severely shape dependent via the internal field. Using the cluster model it is concluded that this dependence plays an important role in the structural transition in the uniaxial stretching process.     

Dialkylzinc additions with a chiral osmaimidazolidine ligand from asymmetric diamination of olefins

A new chiral ligand was prepared in a convenient two-step procedure starting from an asymmetric diamination reaction. Subsequent treatment of the resulting osmaimidazolidine with a phenyl Grignard reagent and titanium tetra(iso-propoxide) furnished a complex that catalyses asymmetric dialkylzinc additions to aromatic aldehydes.     

<Emphasis FontCategory="NonProportional">WHIZARD</Emphasis>—simulating multi-particle processes at LHC and ILC

We describe the universal Monte-Carlo (parton-level) event generator WHIZARD (), version 2. The program automatically computes complete tree-level matrix elements, integrates them over phase space, evaluates distributions of observables, and generates unweighted partonic event samples. These are showered and hadronized by calling external codes, either automatically from within the program or via standard interfaces. There is no conceptual limit on the process complexity; using current hardware, the program has successfully been applied to hard scattering processes with up to eight particles in the final state. Matrix elements are computed as helicity amplitudes, so spin and color correlations are retained. For event generation, processes can be concatenated with full spin correlation, so factorized approximations to cascade decays are possible when complete matrix elements are not desired. The Standard Model, the MSSM, and many alternative models such as Little Higgs, anomalous couplings, or effects of extra dimensions or noncommutative SM extensions have been implemented. Using standard interfaces to parton shower and hadronization programs, WHIZARD covers physics at hadron, lepton, and photon colliders.     

Role of intermolecular interactions on the electronic and geometric structure of a large pi-conjugated molecule adsorbed on a metal surface

The organic semiconductor molecule 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) exhibits two adsorption states on the Ag(111) surface: one in a metastable disordered phase, prepared at low temperatures, the other in the long-range ordered monolayer phase obtained at room temperature. Notably, the two states differ substantial in their vertical bonding distances, intramolecular distortions, and electronic structures. The difference is explained by intermolecular interactions, which are particularly relevant for the long-range ordered phase, and which hence require attention.