Minimizing the Time-Dependent Density Functional Error in Ehrenfest Dynamics

Simulating electron–ion dynamics using time-dependent density functional theory within an Ehrenfest scheme can be done in two ways that are principle exact and identical: propagating electronic Kohn–Sham equations or coefficients on surfaces obtained from linear-response. We show here approximate leads to qualitatively different the approaches. argue latter is more accurate because functionals evaluated domains close ground state where currently used approximations perform better. demonstrate this exactly solvable model of charge transfer discuss implications for time-resolved spectroscopy.