Angular Distributions and Dalitz plots for C6+ ionization of He

S. OTRANTO, J. FIOL, R. E. OLSON

Belfast, Gran Bretaña

Conferencia; The 13th International Conference on the Physics of Highly Charged Ions; 2006

Single ionization fully differential cross sections for 2 MeV/amu C6+ + He collisions are presented and analyzed using the classical trajectory Monte Carlo (CTMC) and Continuum Distorted Wave (CDW) models. The present theoretical results are compared with recent experimental data of Fischer et al [1]. The published experimental conditions are considered in the theoretical models. The inclusion of the target atom momentum uncertainty leads to an improved description of the forward electron emission. Moreover, we present cross sections in the plane perpendicular to that of the collision, and describe how the inclusion of the target momentum spread modifies the angular structures and the intensities. We show that previously reported theory-experiment discrepancies may be removed by convoluting the theoretical cross sections with the experimental resolutions. In the Figure are shown fully differential cross sections (FDCS) in the parallel and perpendicular planes for 2 MeV/amu C6+ + He collisions. The emitted electron energy is 4 eV and the projectile momentum transfer is Q=0.65 a.u. It can be clearly seen that accounting for the target momentum distribution (TMD) improves the theoretical description in the forward direction where the electronic emission is increased by almost a factor 5. This also introduces a sharp increase of the theoretical cross sections in the perpendicular plane. Dalitz plots for single ionization fully differential cross sections in ion-atom collisions will be presented and are used to help elucidate the collision dynamics [2]. References   [1] D. Fischer, R. Moshammer, M. Schulz, A. Voitkiv and J. Ullrich, J. Phys. B: At. Mol. Opt. Phys. 36,  3555 (2003). [2] S. Otranto, R. E. Olson and J. Fiol, J. Phys B 39, L175  (2006).