The method of computer simulations is employed to investigate the two-elect
ron ionization of a model one-dimensional xenonlike atom with a femtosecond
laser pulse. Based on the comparison of the results of exact simulations a
nd calculations performed in the approximation of a "passive" electron, we
analyze the contribution of the rescattering effect to the double ionizatio
n of atoms. It is demonstrated that the formation of doubly charged ions is
not reduced to the rescattering process.