Coincidence studies of He ionized by C{sup 6+}, Au{sup 24+}, and Au{sup 53+}

Journal Article · Thu Apr 15 04:00:00 EDT 2010 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.81.042704· OSTI ID:21408620

McGovern, M; Walters, H R. J. ^[1]; Assafrao, D; Mohallem, J R ^[2]; Whelan, Colm T ^[3]

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1. Department of Applied Mathematics and Theoretical Physics, Queen's University, Belfast BT7 1NN (United Kingdom)
2. Laboratorio de Atomos e Moleculas Especiais, Departamento de Fisica, ICEx, Universidade Federal de Minas Gerais, Caixa postal 702, 30123-970 Belo Horizonte, MG (Brazil)
3. Department of Physics, Old Dominion University, Norfolk, Virginia 23529-0116 (United States)

A recently developed [Phys. Rev. A 79, 042707 (2009)] impact parameter coupled pseudostate approximation (CP) is applied to calculate triple differential cross sections for single ionization of He by C{sup 6+}, Au{sup 24+}, and Au{sup 53+} projectiles at impact energies of 100 and 2 MeV/amu for C{sup 6+} and 3.6 MeV/amu for Au{sup 24+} and Au{sup 53+}. For C{sup 6+}, satisfactory, but not perfect, agreement is found with experimental measurements in coplanar geometry, but there is substantial disagreement with data taken in a perpendicular plane geometry. The CP calculations firmly contradict a projectile-nucleus interaction model which has been used to support the perpendicular plane measurements. For Au{sup 24+} and Au{sup 53+}, there is a complete lack of accord with the available experiments. However, for Au{sup 24+} the theoretical position appears to be quite firm with clear indications of convergence in the CP approximation and very good agreement between CP and the completely different three-distorted-waves eikonal-initial-state (3DW-EIS) approximation. The situation for Au{sup 53+} is different. At the momentum transfers at which the measurements were made, there are doubts about the convergence of the CP approximation and a factor of 2 difference between the CP and 3DW-EIS predictions. The discord between theory and experiment is even greater with the experiment giving cross sections a factor of 10 larger than the theory. A study of the convergence of the CP approximation shows that it improves rapidly with reducing momentum transfer. As a consequence, lower-order cross sections than the triple are quite well converged and present an opportunity for a more reliable test of the experiment.

• OSTI ID: 21408620
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 4 Vol. 81; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
74 ATOMIC AND MOLECULAR PHYSICS
APPROXIMATIONS
CALCULATION METHODS
CONVERGENCE
CROSS SECTIONS
DIFFERENTIAL CROSS SECTIONS
DISTORTED WAVE THEORY
EIKONAL APPROXIMATION
ENERGY RANGE
FORECASTING
GEOMETRY
IMPACT PARAMETER
INTERACTIONS
IONIZATION
MATHEMATICS
MEV RANGE
MOMENTUM TRANSFER
NUCLEI