Extension of the CDW-EIS model for single electron capture in ion-atom collision involving multielectronic targets

P. N. ABUFAGER, A. E. MARTÍNEZ, R. D. RIVAROLA AND P. D. FAINSTEIN

Stockholm

Conferencia; 23rd International Conference on Photonic, Electronic and Atomic Collisions; 2003

We present an extension of the Continuum Distorted Wave - Eikonal Initial State (CDW-EIS) approximation, for the description of single electron capture from multielectronic atoms by impact of bare ions. We develope this approximation within the framework of the independient electron model (IEM) [1] taking particular care on the representation of the bound and continuum target states. In a previous work [2], the interaction between the active and the passive electrons of the target was treated asymmetrically in the incoming and outgoing channels. Roothaan-Hartree-Fock[3] wavefunctions were employed to describe the target bound states and continuum Coulomb wavefunctions with effective charge[1] Z_D were introduced to represent the distorsion produced by the active electron - residual target interaction in the final channel. In the present extension of the CDW-EIS approximation, the potential due to the target is represented by a spherically symmetric model potential in both the initial and final channels. Therefore, bound and continuum target states result ortogonal wavefunctions. These wavefunctions are obtained by solving numerically one electron Schrodinger equations with Hartree-Fock-Slater model potentials[4]. We apply this model to the study of single electron capture from the K shell of He, Ne and Ar noble gases by impact of H+, He(2+) and Li(3+). The total cross sections obtained with the extended CDW-EIS approximation provide an excellent description of the experimental data$^{5,6}$, improving remarkably the previous results, even at intermediate energies. 1. Dz Belkic, R Gayet and A. Salin; Phys. Rep. 56, 279 (1979) 2. Martinez, A. E., Deco, G. R., Rivarola, R. D. and Fainstein, P.D., Nucl. Instrum. Methods B 34, 32 (1988). 3. E. Clementi and C. Roetti; Atom. Data Nucl. Date Tables 14, 177, (1974) 4. F. Herman and S. Skillman; Atomic Structure Calculations (Prentice Hall Inc., Englewood Cliffs, NJ, 1963) 5 E.Horsdal-Pedersen et al., J. Phys.B, 16, 1799 (1983) 6. J.R.Macdonald et al Phys. Rev. Lett. 32 648,(1974)