Time-resolved photoabsorption in finite systems: A first-principles NEGF approach

E. Perfetto, A.-M. Uimonen, R. van Leeuwen, G. Stefanucci
2016 Journal of Physics, Conference Series  
We describe a first-principles NonEquilibrium Green's Function (NEGF) approach to time-resolved photoabsortion spectroscopy in atomic and nanoscale systems. The method is used to highlight a recently discovered dynamical correlation effect in the spectrum of a Krypton gas subject to a strong ionizing pump pulse. We propose a minimal model that captures the effect, and study the performance of time-local approximations versus time-nonlocal ones. In particular we implement the time-local
more » ... time-local Hartree-Fock and Markovian second Born (2B) approximation as well as the exact adiabatic approximation within the Time-Dependent Density Functional Theory framework. For the time-nonlocal approximation we instead use the 2B one. We provide enough convincing evidence for the fact that a proper description of the spectrum of an evolving admixture of ionizing atoms requires the simultaneous occurrence of correlation and memory effects.
doi:10.1088/1742-6596/696/1/012004 fatcat:e2in43lbcnekrmbdc4mso7kgzi