The energy analysis of time-dependent numerical wave functions

A new method for extracting energy-resolved quantities from a wave function calculated on a numerical grid is presented. The method is fast, flexible and is easily applied in multiple dimensions. A number of its features are illustrated via a calculation of the short-pulse laser ionization spectrum of hydrogen. This spectrum exhibits many narrow resonances, ranging over eight orders of magnitude in the continuum, as well as significant bound-state populations and so forms a rigorous test of the method. (orig.)