https://doi.org/10.1140/epjd/e2017-80584-8
Regular Article
Electronic excitation cross section in positron scattering by H2 molecules using distorted-wave method★
1
Departamento Acadêmico de Física, Universidade Tecnológica Federal do Paraná,
85503-390
Pato Branco,
PR, Brazil
2
Departamento de Física, Universidade Federal de Santa Catarina,
88040-900
Florianópolis,
SC, Brazil
3
Departamento de Física, Universidade Federal do Paraná,
81531-980
Curitiba,
PR, Brazil
a e-mail: luciara@utfpr.edu.br
Received:
14
September
2017
Received in final form:
1
December
2017
Published online: 8
February
2018
In this work we have applied for the first time the distorted-wave approximation (DWA) combined with Schwinger Variational Iterative Method (SVIM) to describe electronic excitation of H2 molecules by positron collisions. The integral (ICS) and differential (DCS) excitation cross sections for X1Σg+ → B1Σu+ transition of H2 molecule, in the range from near threshold up to 45 eV of positron energies, were reported in static (ST) and static-correlation-polarization (STPOL) levels. Our two-state ICS in DWA-ST level have quantitative agreement with experimental measurement at energies from threshold up to 18 eV and the inclusion of polarization effects increases the cross sections. Comparison with 2-state close-coupling approximation (CCA), 2-state Schwinger Multichannel (SMC), 5-state SMC and 1013-state from Convergent Close-Coupling (CCC) methods are done and is encouraging. The relative steeper drop above 22 eV in experimental ICS was not observed by any theoretical calculations indicating that new measurements would be interesting for this transition in this energy range.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2018