Stabilization phenomenon revisited in attosecond regime: Applicability of a regularized potential

We present the results of numerical simulations performed for a realistic model of the hydrogen atom as well as for a model with a smoothed core, both in the presence of the strong linearly polarized laser field in the attosecond regime. These results generally confirm the existence of stabilization in 3D ionization, although there are some significant quantitative discrepancies in comparison to earlier reports, which may be important in the context of possible future experiments. We have also checked the applicability of the smoothed model potential and the rectangular pulse shape for the photoionization process in the strong field and ultra-short time regime. Both simplifications strongly influence the numerical effort necessary in ab initio simulations and thus its duration. In contrast to the 1D case, in which the results obtained using the potential with a smoothed core are essentially different from those for a singular potential, in the 3D case removing the singularity does not lead to such a strong discrepancy: the stabilization is visible though the depth and range of the stabilization window are different. Thus it may serve as a useful model of some aspects of the real hydrogen atom, which allows one to significantly shorten 3D computations.