On the computation of momentum distributions within wavepacket propagationcalculations

Abstract

We present a new method to extract momentum distributions from time-dependentwavepacket calculations. In contrast to established Fourier transformation of thespatial wavepacket at a fixed time, the proposed ‘virtual detector’ methodexamines the time dependence of the wavepacket at a fixed position. In firstapplications to the ionization of model atoms and the dissociation of H2+,we find a significant reduction of computing time and are able to extract reliablefragment momentum distributions by using a comparatively small spatialnumerical grid for the time-dependent wavefunction.