Translational energy dependence of reaction mechanism: Xe++CH4→XeH++CH3

This is the publisher's version, also available electronically from http://scitation.aip.org/content/aip/journal/jcp/74/9/10.1063/1.441715.The dynamics of the exoergic ion–molecule reaction Xe+(CH4,CH3)XeH+ were studied by chemical accelerator techniques over the relative translational energy range 0.2 to 8 eV. Results of the kinematicmeasurements are reported as scattering intensity contour maps in Cartesian velocity space. Center‐of‐mass angular and energy distributions, derived from these maps, provide information on the reaction mechanism and on the partitioning of available energy between internal and translational modes in the products. The results suggest that reaction proceeds via the formation of a long‐lived complex at low collision energies (below 0.5 eV) and by a direct mechanism approaching spectator stripping at higher energies

Role of impact parameter in branching reactions: Chemical accelerator studies of the reaction Xe++CH4→XeCH3 ++H

This is the publisher's version, also available electronically from http://scitation.aip.org/content/aip/journal/jcp/74/9/10.1063/1.441716.Integral reaction cross sections and product velocity distributions have been measured for the ion–molecule reaction Xe+(CH4,H)XeCH3 + over the relative reactant translational energy range of 0.7–5.5 eV by chemical accelerator techniques. The kinematic results indicate that reaction proceeds in a direct manner by a rebound mechanism over the energy range studied, suggesting that this substitution reaction occurs predominantly in small impact parameter collisions. This finding contrasts with the results obtained for the competing reaction, Xe+(CH4,CH3)XeH+, where the strong forward scattering of the XeH+ product indicates that H‐atom abstraction occurs primarily in large impact parameter collisions

Excited hadrons on the lattice: Baryons

We present results for masses of excited baryons from a quenched calculation with Chirally Improved quarks at pion masses down to 350 MeV. Our analysis of the correlators is based on the variational method. In order to provide a large basis set for spanning the physical states, we use interpolators with different Dirac structures and Jacobi smeared quark sources of different width. Our spectroscopy results for a wide range of ground state and excited baryons are discussed