arXiv subjects

Anna Baranova

Publications and source records attributed to Anna Baranova.

3 recordsLinked to original sources

arXiv2025

Harnessing dressed time-dependent density functional theory for the non-perturbative regime: Electron dynamics with double excitations

Recent progress has been made in capturing spectral features of electronic states of double-excitation character in time-dependent density functional theory (TDDFT) through a frequency-dependent kernel. While it might appear that this development is limited to the perturbative regime, we show that when used within response-reformulated TDDFT, it accurately captures strong-field dynamics involving states of double-excitation character. More generally, this demonstrates how RR-TDDFT enables exchange-correlation functional developments in the response regime, which have so far been more successful than those in the non-linear regime, to be exploited for non-perturbative dynamics, thus significantly broadening their range of applications.

physics.chem-ph↗

arXiv2025

Excited State Densities from Time-Dependent Density Functional Response Theory

While the variational principle for excited-state energies leads to a route to obtaining excited-state densities from time-dependent density functional theory, relatively little attention has been paid to the quality of the resulting densities in real space obtained with different exchange-correlation functional approximations, nor how non-adiabatic approximations developed for energies of states of double excitation character perform for their densities. Here we derive an expression directly in real space for the excited-state density, that includes the case of non-adiabatic kernels, and consequently is able, for the first time, to yield densities of states of double-excitation character. Under some well-defined simplifications, we compare the performance of the local-density approximation and exact-exchange approximation, which are in a sense at opposite extremes of the fundamental functional approximations, on local and charge-transfer excitations in one-dimensional model systems, and show that the dressed TDDFT approach gives good densities of double-excitations.

physics.chem-ph↗

arXiv2024

Reformulation of Time-Dependent Density Functional Theory for Non-Perturbative Dynamics: The Rabi Oscillation Problem Resolved

Rabi oscillations have long been thought to be out of reach in simulations using time-dependent density functional theory (TDDFT), a prominent symptom of the failure of the adiabatic approximation for non-perturbative dynamics. We present a reformulation of TDDFT which requires response quantities only, thus enabling an adiabatic approximation to predict such dynamics accurately because the functional is evaluated on a density close to the ground-state, instead of on the fully non-perturbative density. Our reformulation applies to it any real-time dynamics, redeeming TDDFT far from equilibrium. Examples of a resonantly-driven local excitation in a model He atom, and charge-transfer in the LiCN molecule are given.

physics.chem-ph↗