Schwinger multichannel method for positron-molecule scattering

Journal Article · Sat May 01 04:00:00 EDT 1993 · Physical Review A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.47.3976· OSTI ID:6609385

Germano, J S.E. ^[1]; Lima, M A.P. ^[2]

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1. Instituto Tecnologico da Aeronautica, Centro Tecnico Aeroespacial, 12200 S. J. Campos, Sao Paulo (Brazil)
2. Instituto de Fisica Gleb Wataghin,'' Universidade Estadual de Campinas, 13081, Campinas, Sao Paulo (Brazil)

We present a formulation for low-energy positron-molecule collisions based on the Schwinger multichannel method (SMC) which was previously adapted for electron-molecule scattering. We have preserved very important features of the SMC such as its ability to deal with electronically inelastic scattering and its applicability to molecular targets of arbitrary geometry. Our implementation also allows for the inclusion of a substantial number of closed electronic channels to represent polarization effects, which are very important at low impact energies. As an application, to illustrate the form with which polarization is represented in this formulation, we have calculated elastic integral and differential cross sections for [ital e][sup +-]H[sub 2] and [ital e][sup +-]CH[sub 4] collisions. We included all possible single-particle excitations from the target and found substantial disagreement with respect to model potential calculations and attenuated-beam experimental data. We discuss possible reasons for these discrepancies.

• OSTI ID: 6609385
• Journal Information: Physical Review A; (United States), Journal Name: Physical Review A; (United States) Vol. 47:5; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

664500* -- Special Atoms & Molecules-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ALKANES
ANNIHILATION
BASIC INTERACTIONS
CALCULATION METHODS
COLLISIONS
CROSS SECTIONS
DIFFERENTIAL CROSS SECTIONS
ELASTIC SCATTERING
ELECTROMAGNETIC INTERACTIONS
ELEMENTS
ENERGY DEPENDENCE
HYDROCARBONS
HYDROGEN
INELASTIC SCATTERING
INTERACTIONS
METHANE
MOLECULE COLLISIONS
NONMETALS
ORGANIC COMPOUNDS
PARTICLE INTERACTIONS
POSITRON COLLISIONS
POSITRON-MOLECULE COLLISIONS
SCATTERING
SCHWINGER VARIATIONAL METHOD
TOTAL CROSS SECTIONS
VARIATIONAL METHODS