DFT beyond the ground-state: memory-dependent functionals and coupling to ions

The adiabatic approximations currently used in time-dependent density functionals describe exchange-correlation effects that depend only on the instantaneous density. However, recent work has shown that dependence on the history of the density and initial states is important to incorporate for accurate simulations of the dynamics, especially for systems driven far from the ground-state. In many applications when strong lasers are involved, the electron and nuclear dynamics happen on a similar time-scale, especially when light nuclei are present, and the effects of correlation between the electron dynamics and quantum ion dynamics can be significant.
I will present some recent developments in our group building memory-dependent functional approximations starting from an exact expression, and including correlated electron-ion dynamics via the exact factorization approach.