Effects of orbital and Coulomb potential in strong-field nonadiabatic tunneling ionization of atoms

We study the intensity-dependent photoelectron differential momentum distributions from tunneling ionization of Kr and Xe atoms in circularly polarized laser fields. We measure the width of photoelectron momentum distribution along the laser propagation direction in conjunction with the most probable momentum in the polarization plane. The predictions of the available tunneling models do not agree with the measurement. We further present a semiclassical model for strong-field tunneling ionization of atoms in circularly polarized laser fields, in which we include the effect of the initial orbitals with different magnetic quantum numbers. Using this model, we quantify the relative contributions of the initial orbitals with different magnetic quantum numbers to the photoelectron differential momentum distributions. We achieve good agreement with the measurement, which does not depend on calibration of the laser intensity. Both the atomic orbitals and the long-range Coulomb potential have significant effects on the quantitative description of strong-field tunneling ionization of atoms.