Time-dependent density-functional and reduced density-matrix methods for few electrons: Exact versus adiabatic approximations
Chemical Physics 391, 1 - 10 (2011)
Time-dependent density-functional and reduced density-matrix methods for few electrons: Exact versus adiabatic approximations
To address the impact of electron correlations in the linear and non-linear re- sponse regimes of interacting many-electron systems exposed to time-dependent external fields, we study one-dimensional (1D) systems where the interacting problem is solved exactly by exploiting the mapping of the 1D N -electron prob- lem onto an N -dimensional single electron problem. We analyze the perfor- mance of the recently derived 1D local density approximation (LDA) as well as the exact-exchange (EXX) orbital functional for those systems. We show that the interaction with an external resonant laser field shows Rabi oscillations which are detuned due to the lack of memory in adiabatic approximations. To investigate situations where static correlations play a role, we consider the time-evolution of the natural occupation numbers associated to the reduced one-body density matrix. Those studies shed light on the non-locality and time-dependence of the exchange and correlation functionals in time-dependent density and density-matrix functional theories.
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- http://dx.doi.org/10.1016/j.chemphys.2011.06.010