Physical Review A
Reply to ‘‘Comment on ‘Multiphoton-ionization transition amplitudes and the Keldysh approximation’ ’’
Fabio Trombetta, S. Basile, G. Ferrante
Abstract
We reply to the preceding Comment by Antunes Neto, Davidovich, and Milonni [Phys. Rev. A 41, 4095 (1990)] on our paper dealing with the Keldysh approximation for multiphoton ionization of atoms [Phys. Rev. A 40, 2774 (1989)]. We show by a concrete example how the replacement of the free evolution operator by the atomic one, leading to the Keldysh transition amplitude, can be justified for weak- and short-range binding potentials.