Numéro
J. Phys. IV France
Volume 03, Numéro C4, Septembre 1993
4th International Workshop on Positron and Positronium Chemistry
Page(s) C4-69 - C4-76
DOI http://dx.doi.org/10.1051/jp4:1993407
4th International Workshop on Positron and Positronium Chemistry

J. Phys. IV France 03 (1993) C4-69-C4-76

DOI: 10.1051/jp4:1993407

Positronium chemistry studied by AMOC measurements using a relativistic positron beam

H. SCHNEIDER1, A. SEEGER1, 2, A. SIEGLE2, H. STOLL1, I. BILLARD3, M. KOCH1, U. LAUFF1 and J. MAJOR1

1  Max-Planck-Institut für Metallforschung, Institut für Physik, Heisenbergstr. 1, 70569 Stuttgart, Germany
2  Universität Stuttgart, Institut für Theoretische und Angewandte Physik, 70569 Stuttgart, Germany
3  Centre de Recherches Nucléaires, Laboratoire de Chimie Nucléaire, BP. 20, 67037 Strasbourg cedex, France


Abstract
Beam-based Age-Momentum Correlation (β+γΔE AMOC) measurements using an MeV positron beam have become a powerful tool to study chemical reactions of positronium by time-domain observations of the different positron states tagged by the Doppler-broadening (ΔE) characteristics of the 511 keV annihilation radiation. As an example, the investigation of the spin-conversion reaction in the system HTEMPO/methanol is reported. The experimental data for small HTEMPO concentrations can be fitted quite well to a rate-equation model containing the conversion rate as the only adjustable parameter. This model can presumably be applied not only to spin conversion but also to other chemical reactions and to inhibition of positronium. Possible effects of oxidation, complex formation, and inhibition are discussed by way of examples.



© EDP Sciences 1993