Polymerization of propadiene. III. Catalyst systems based on various rhodium (I) complexes

The polymerization of propadiene to 1,2-polyallene by various Rh(I) based catalysts is described and discussed. Also the interrelations between these Rh(I) complexes are discussed and an overall reaction scheme is given. A mechanism is put forward in which the formation of a common intermediate from propadiene and different Rh(I) complexes is the rate determining step. It is found that the activity decreases in the order: cis-Rh(CO)₂P(C₆H₅)₃Cl > [Rh(CO)₂Cl]₂ > Rh(CO)₃Cl. The complexes Rh[P(C₆H₅)₃]₂(CO)Cl and Rh[P(C₆H₅)₃]₃Cl proved to be inactive in the polymerization of propadiene.     

Triple Regge analysis of inclusiveΛ production inK + p and π+ p interactions at 250 GeV/c

A triple Regge analysis is performedof inclusive production in the proton fragmentation region ofK ⁺+X and ⁺+X at 250 GeV/c. Slope and intercept of the leading strange meson trajectory are determined. The results obtained here are compared with those of other experiments.Partially supported by grants from CPBP 01.06 and 01.09.     

A study of double pomeron exchange inπ + p andK + p interactions at 250 GeV/c

Using the ARGUS detector at thee ⁺ e ^– storage ring DORIS II at DESY, we have measured the inclusive production ofD ⁰,D ⁺ andD ^*(2010)⁺ mesons inB decays and in nonresonante ⁺ e ^– annihilation around 10.6 GeV. The inclusive branching ratios forB decays toD ⁰,D ⁺ andD ^*+ mesons are found to be (52.2±8.2±3.5)%, (27.2±6.3±3.5)% and (34.8±6.0±3.5)% respectively. Thus,D ⁰ andD ⁺ production account for about 70% of the charm produced inB decays, neglectingbu contributions to the total width. The production cross sections and momentum spectra for continuume ⁺ e ^– annihilation are also presented.Supported by the German Bundesministerium für Forschung und Technologie, under contract number 054DO51P     

Exclusive measurement of quasifree proton-neutron bremsstrahlung

Data on proton-neutron bremsstrahlung have been obtained from a measurement of the quasifree breakup channel in proton-deuteron bremsstrahlung. This high-precision measurement, with an incident proton energy of 190 MeV, is fully exclusive; i.e., the protons, the neutron, and the photon have been detected. The quasifree differential cross sections obtained are compared with microscopic calculations and calculations based on soft-photon models. There are sizable differences between the models and also between the models and the data obtained for this simple process.