A Missing Reaction Step in Dithiobenzoate-Mediated RAFT Polymerization

The debate on the mechanism of dithiobenzoate-mediated RAFT polymerization may be overcome by taking the so-called “missing step” reaction between a highly reactive propagating radical and the three-arm star-shaped product of the combination reaction of an intermediate RAFT radical and a propagating radical into account. The “missing step” reaction transforms a propagating radical and a not overly stable three-arm star species into a resonance-stabilized RAFT intermediate radical and a stable polymer molecule. The enormous driving force behind the “missing step” reaction is estimated via DFT calculations of reaction enthalpies and reaction free enthalpies.     

Electro-optical properties of InGaAs layers grown by hydride vapour phase epitaxy

A series of epitaxial layers of the InGaAs alloy were deposited on (001) oriented InP substrates by using hydride VPE technique. The layers were characterized by Double Crystal Diffractometry (DCD), Photoluminescence (PL), Hall effect and Capacitance-Voltage (C-V) measurements. The growth parameters and the quality of the grown layers are discussed on the basis of electrical and structural data analysis.     

Consequences of Crossed Channel Structure for High Energy Elastic Scattering

This review describes a field in the S-matrix theory of elastic stattering. Analyticity and elastic unitarity in the crossed t-channel are shown in a rigorous manner to yield constraints on s-channel quantities. Strong restrictions on s-channel partial wave with angular momenta l ⩾√s/2(b₀ + λ In s) follow from realistic assumptions on the amplitude in the unphysical domain (Mandelstam analyticity and Regge behaviour). The possibility of phenomenological application of these results is discussed.