Virtual detector methods for efficiently computing ionization and dissociating spectra

We discuss a flux-based ``virtual detector'' method for computing momentum-resolved dissociation and ionization spectra by analyzing the motion of quantum mechanical wavepackets at the periphery of their numerical grids. We extended prior semi-classical applications of this method [1-4] by systematically including quantum mechanical corrections. Using examples of atomic ionization and diatomic molecular dissociation, we discuss the numerical convergence properties and computational efficiency of this computational method. We also compare the numerical efficiency of virtual detection to Fourier transformation methods for extracting momentum spectra from time-dependent quantum mechanical calculations. [1] Feuerstein, B. and U. Thumm, J. Phys. B \textbf{36}, 707 (2003). [2] Magrakvelidze, M. \textit{et al.}, Phys. Rev. A \textbf{86}, 023402 (2012). [3] Wang. X. \textit{et al.,} Phys. Rev. Lett. \textbf{110}, 243001 (2013). [4] Teeny, N. \textit{et al.,} Phys. Rev. A \textbf{94}, 022102 (2016).