Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/104933
Type: Artigo de periódico
Title: Near-threshold Vibrational Excitation Of H2 By Positron Impact: A Projection-operator Approach
Author: Varella M.T.D.N.
Lima M.A.P.
Abstract: We report vibrational excitation (νi =0→ νf =1) and total cross sections for positron scattering by H2. The Feshbach projection operator formalism was employed to vibrationally resolve the fixed-nuclei phase shifts obtained with the Schwinger multichannel method. The near-threshold behavior of the vibrational excitation cross section is in good agreement with available experimental data. Though our fixed-nuclei calculations do not indicate the existence of a e+ - H2 virtual state, a proper description of the T matrix threshold behavior is essential (the adiabatic approximation is inadequate). The projection operator approach has long been a powerful tool for studies of nuclear dynamics in electron-molecule collisions, and its application to positron scattering is timely since couplings to nuclear degrees of freedom are known to be very important at low impact energies. © 2007 The American Physical Society.
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Rights: aberto
Identifier DOI: 10.1103/PhysRevA.76.052701
Address: http://www.scopus.com/inward/record.url?eid=2-s2.0-36048957498&partnerID=40&md5=d8a0ce1a6d7513a604ff0d3711e2311e
Date Issue: 2007
Appears in Collections:Unicamp - Artigos e Outros Documentos

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