Real-time dynamics of Auger wavepackets and decays in ultrafast charge migration processes

The Auger decay is a relevant recombination channel during the first few femtoseconds of molecular targets impinged by attosecond XUV or soft X-ray pulses. Including this mechanism in time--dependent simulations of charge--migration processes is a difficult task, and Auger scatterings are often ignored altogether. In this work we present an advance of the current state-of-the-art by putting forward a real--time approach based on nonequilibrium Green's functions suitable for first-principles calculations of molecules with tens of active electrons. To demonstrate the accuracy of the method we report comparisons against accurate grid simulations of one-dimensional systems. We also predict a highly asymmetric profile of the Auger wavepacket, with a long tail exhibiting ripples temporally spaced by the inverse of the Auger energy.