BEYOND THE STRONG FIELD MODEL IN ATOMIC SINGLE PHOTOIONIZATION

D. G. ARBÓ; J. E. MIRAGLIA; M. S. GRAVIELLE; P. A. MACRI; V. D. RODRIGUEZ; K. TÖKÉSI; K. SCHIESSL; E. PERSSON; J. BURGDÖRFER

Freiburg, Germany

Congreso; 25th International Conference on Photonic, electronic and Atomic Collisions; 2007

ICPEAC

We investigate the effect of the Coulomb potential of the atomic core on the dynamics of the detached electron for single ionization by strong short-laser pulses. In the present work, we make use of a timedependent distorted-wave theory – the Coulomb-Volkov (CV) approach, which allows us to consider the effect of the remaining core at the same level of approximation. In this way, we can probe the effect of the core potential on the dynamics of the detached electron. We compare CV and the standard Volkov (V) approximation with full numerical results of the time-dependent Schrödinger equation (TDSE). The V model is not adequate to resemble the full electron emission momentum spectrum, i.e., the near-threshold interference structure  and the cusp of the transverse momentum distribution. In turn, as the distorted final state in the CV theory includes the distortion introduced by the Coulomb potential, it reproduces the low-energy interference pattern as also the cusp in the transversal momentum. A study of the momentum distributions for zero carrier-envelope phase shows that the CV theory accounts also for the backward-forward asymmetry. This is not the case for the V theory, which predicts a sinusoidal function of the asymmetry coefficient as a function of the carrierenvelope phase (CEP). Work supported by Conicet (Argentina), the Argentina-Hungary collaboration HU/PA05- EIII/007, and SFB 016 ADLIS of the FWF(Austria).