ANNIHILATION DYNAMICS OF POSITRONS IN MOLECULAR ENVIRONMENTS

Authors
DASILVA EP GERMANO JSE LINO JLS DECARVALHO CRC NATALENSE APP LIMA MAP
Citation
Ep. Dasilva et al., ANNIHILATION DYNAMICS OF POSITRONS IN MOLECULAR ENVIRONMENTS, Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms, 143(1-2), 1998, pp. 140-148
Citations number
11
Categorie Soggetti
Instument & Instrumentation","Nuclear Sciences & Tecnology","Physics, Atomic, Molecular & Chemical","Physics, Nuclear
Journal title
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms → ACNP
ISSN journal
0168583X
Volume
143
Issue
1-2
Year of publication
1998
Pages
140 - 148
Database
ISI
SICI code
0168-583X(1998)143:1-2<140:ADOPIM>2.0.ZU;2-8
Abstract
We present recent results for positron-molecule scattering obtained wi th the Schwinger multichannel method. Our calculations include integra l, differential and momentum transfer cross sections and the annihilat ion parameter Z(eff) for C2H2 and C2H4 molecules. We discuss a mechani sm for annihilation of positrons in low-energy positron-molecule scatt ering. We interpret the annihilation process through virtual electroni c excitation of the target combined with electronic cloud relaxation a nd virtual positronium formation. We study the influence of the first electronic state of the target on the cross section and on the annihil ation parameter in e(+)-C2H2 scattering. (C) 1998 Elsevier Science B.V . All rights reserved.