Adiabatic approximation of time-dependent density matrix functional response theory.

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 response 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 problem onto an N -dimensional single electron problem. We analyze the performance of the ...

The adiabatic approximation in time-dependent density matrix functional theory: response properties from dynamics of phase-including natural orbitals.

The adiabatic approximation is problematic in time-dependent density matrix functional theory. With pure density matrix functionals (invariant under phase change of the natural orbitals) it leads to lack of response in the occupation numbers, hence wrong frequency dependent responses, in particular α(ω→0)≠α(0) (the static polarizability). We propose to relinquish the requirement that the functi...

Time-Dependent One-Body Reduced Density Matrix Functional Theory Adiabatic Approximations and Beyond

Excitation energies of dissociating H2: A problematic case for the adiabatic approximation of time-dependent density functional theory

Time-dependent density functional theory ~TDDFT! is applied for calculation of the excitation energies of the dissociating H2 molecule. The standard TDDFT method of adiabatic local density approximation ~ALDA! totally fails to reproduce the potential curve for the lowest excited singlet Su 1 state of H2. Analysis of the eigenvalue problem for the excitation energies as well as direct derivation...

Charge transfer, double and bond-breaking excitations with time-dependent density matrix functional theory.

Time-dependent density functional theory (TDDFT) in its current adiabatic implementations exhibits three remarkable failures: (a) completely wrong behavior of the excited state surface along a bond-breaking coordinate; (b) lack of doubly excited configurations; (c) much too low charge transfer excitation energies. These TDDFT failure cases are all strikingly exhibited by prototype two-electron ...