Quantum interferences in single ionization of He by highly charged dressed-ions impact

MONTI, JUAN MANUEL; FAINSTEIN, PABLO DANIEL; RIVAROLA, ROBERTO DANIEL

Salamanca, España

Conferencia; ECAMP 2010 - 10th International Conference on Atoms, Molecules and Photons; 2010

<!-- @page { margin: 2cm } P { margin-bottom: 0.21cm } -->Through many years the Continuum Distorted Wave-Eikonal Initial State (CDW-EIS) model [1] has shown to be a reliable method to calculate single ionization differential and total cross sections for different projectile/target combinations from intermediate to high non-relativistic impact energies. However, some experimental results can still not be fully described with the existing theories. This is the case of the results obtained by Horst Schmidt-Böcking’s group [2] for the electron emission spectra as a function of electron energy and angle in the region of the binary-encounter peak for 1 MeV/u U21+impinging on He. The spectra showed structures superimposed on the peak. Reinhold et al ([2], see also Schultz and Olson [3]), using a combination of quantum-mechanical and classical descriptions, showed that these structures were due to quantum effects in the elastic differential cross section for the scattering of the ionized target electron with the impinging clothed ion. In a previous work [4] we have extended the CDW-EIS model to consider dressed-ion impact on He with a particular representation of the projectile potential as given by Green and co-workers [5]. These analytical potentials can be separated in a short-range contribution and a long-range Coulomb potential due to the asymptotic screened projectile charge. This theoretical method was applied with success to describe the U21+ + He spectrum. The structures in the doubly differential cross section could be explained as arising from the interference of short- and long-range amplitudes. In the present work we apply our model to the case of single ionization of He by impact of 600 keV/u Au11+ ions. For this case, experimental results obtained by Wolff et al [6] cover a large range of electron energy and angles and show similar interference effects as those found by Schmidt-Böcking’s group. The theoretical results show a good qualitative agreement with the experiments. Details will be given at the Conference. References: [1] Fainstein P D, Ponce V H and Rivarola R D 1991 J. Phys. B: At. Mol. Opt. Phys. 24 3091 [2] Reinhold C O et al 1991 Phys. Rev. Lett.66 1842 [3] Schultz D R and Olson R E 1991 J. Phys. B: At. Mol. Opt. Phys. 24 3409 [4] Monti J M, Fainstein P D and Rivarola R D 2008 J. Phys. B: At. Mol. Opt. Phys. 41 201001 [5] Green A E S, Sellin D L and Zachor A S 1969 Phys. Rev. 184 1 [6] Wolff W et al 1992 J. Phys. B: At. Mol. Opt. Phys.25 3683