Ionization of H-by a strong ultrashort laser pulse

We compare the outcome of two different numerical methods aimed at solving the time-dependent Schrodinger equation associated with the interaction of H- with an ultrashort laser pulse. These methods of spectral and configuration interaction type are based on an expansion of the total wavefunction on eigenstates of H- built as products of either B-spline or complex Sturmian functions. A careful analysis of our results together with a comparison with other existing theoretical data sheds some light on subtle aspects of the theoretical treatments of H- in a strong laser field. A particular emphasis is put on the crucial role played by the density of states in the continua.