Benchmarking Nonequilibrium Green’s Functions against Configuration Interaction for time-dependent Auger decay processes

European Physical Journal B 91: 216 (2018)

Benchmarking Nonequilibrium Green’s Functions against Configuration Interaction for time-dependent Auger decay processes

F. Covito, E. Perfetto, A. Rubio, G. Stefanucci

We have recently proposed a Nonequilibrium Green's Function (NEGF) approach to include Auger decay processes in the ultrafast dynamics of those electrons remaining confined in the parent molecule after photoionization. Within the so called Generalized Kadanoff-Baym Ansatz the fundamental unknowns of the NEGF equations are the reduced one-particle density matrix in the bound sector and the occupations of the continuum states. Both unknowns are one-time functions like the density in Time-Dependent Functional Theory (TDDFT). In this work we assess the accuracy of the approach against Configuration Interaction (CI) calculations in one-dimensional model systems. Our results show that NEGF correctly captures qualitative and quantitative features of the relaxation dynamics provided that the energy of the Auger electron is much larger than the Coulomb repulsion between two holes in the valence shells. For the accuracy of the results dynamical electronelectron correlations or, equivalently, memory effects play a pivotal role. The combination of our NEGF approach with the Sham-Schluter equation may provide useful insights for the development of TDDFT exchange-correlation potentials with a history dependence.

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Doi
http://dx.doi.org/10.1140/epjb/e2018-90161-2
arxiv
http://arxiv.org/abs/1810.01725
Notes
G.S. and E.P. acknowledge EC funding through the RISE Co-ExAN (Grant No. GA644076). E.P. also acknowledges funding from the European Union project MaX Materials design at the eXascale H2020-EINFRA-2015-1, Grant Agreement No. 676598 and Nanoscience Foundries and Fine Analysis- Europe H2020-INFRAIA-2014-2015, Grant Agreement No. 654360. F.C and A.R. acknowledge financial support from the European Research Council (ERC-2015- AdG-694097), Grupos Consolidados (IT578-13) and European Union Horizon 2020 program under Grant Agreement 676580 (NOMAD).

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