Frequency- and wavevector-dependent exchange-correlation kernel for TDDFT

Develop a parametrized exchange-correlation kernel f_xc(q,ω) for the homogeneous electron gas that accurately covers sufficiently large ranges of both wavevector q and frequency ω, thereby enabling a comprehensive description of dynamical effects in time-dependent density-functional theory.

Background

The paper models the two-dimensional homogeneous electron gas using a static DPGT exchange-correlation kernel derived from quantum Monte Carlo data and supplements it with the frequency-dependent NCT parametrization to estimate dynamical effects. The authors note that this combination is not a fully parametrized treatment of both wavevector and frequency dependence.

A broadly applicable kernel covering sufficiently large ranges of both variables would improve the quantitative description of collective excitations and response functions in TDDFT. The authors explicitly identify deriving such a kernel as a major unresolved challenge.