Nonexistence of a “local suppression“ in the ionization of hydrogen atoms by a low-frequency laser field of arbitrary strength

摘要

Further development of an analytical model for the tunneling ionization of atoms using a low-frequency lasernfield of arbitrary strength, including the strong-field region, is presented. The model uses a very accurate approximation ofnthe true ionization barrier–potential in the Schrödinger equation by the effective parabolic barrier–potential based on the algorithmnsuggested by Miller and Good and later employed by Kulyagin and Taranukhin (KT) for calculating the ionizationnrate, W(F), of hydrogen atoms from the ground state by a linearly polarized laser field. We point out and eliminate a numbernof principal errors made by KT and calculate W(F) much more accurately. We demonstrate that the dependence of thenionization rate on the strength of the linearly polarized laser field is monotonic and does not show any effect of the stabilizationn(“local ionization suppression”) claimed by KT. Our results for W(F) are in good agreement with the results of quantumnfully numerical simulations. The analytical method, further developed in the present paper, can be extended without difficultynto calculations of the tunneling ionization for a number of other quantum systems. The most immediate extensions arento hydrogen atoms in an elliptically polarized laser field and atoms described by the Thomas–Fermi model.