Comprehensive benchmarking of density matrix functional approximations

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 ...

Density-functional approximations for exchange and correlation

Density-functional theory (DFT) is based on two pivotal theorems due to Hohenberg and Kohn [1]. The first theorem states that the ground-state density ρ(r) of a system of electrons uniquely determines the Hamiltonian and hence all properties that can be derived from it. Using mathematical language we can say that the total electronic energy of the system is a functional of the electron density,

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

From Density Functional Theory to Density Matrix Functional Theory

Coupled cluster methods are considered among the most accurate tools in electronic structure theory. Nonetheless relatively limited attempt seems to have been made to extend their applicability to the description of the core-excitation phenomena that are behind largely used spectroscopic techniques like x-ray absorption spectroscopy and x-ray circular dichroism. As a first step to redeem for su...

Benchmarking the performance of time-dependent density functional methods.

The performance of 24 density functionals, including 14 meta-generalized gradient approximation (mGGA) functionals, is assessed for the calculation of vertical excitation energies against an experimental benchmark set comprising 14 small- to medium-sized compounds with 101 total excited states. The experimental benchmark set consists of singlet, triplet, valence, and Rydberg excited states. The...