Universal Dynamical Steps in the Exact Time-Dependent Exchange-Correlation Potential

PETER ELLIOT; JOHANNA I FUKS; ANGEL RUBIO; NEEPA T. MAITRA

PHYSICAL REVIEW LETTERS

AMER PHYSICAL SOC

Lugar: New York; Año: 2012 vol. 109

0031-9007

We show that the exact exchange-correlation potential of time-dependent density-functional theorydisplays dynamical step structures that have a spatially nonlocal and time nonlocal dependence on thedensity. Using one-dimensional two-electron model systems, we illustrate these steps for a range ofnonequilibrium dynamical situations relevant for modeling of photochemical or physical processes: field-free evolution of a nonstationary state, resonant local excitation, resonant complete charge transfer, andevolution under an arbitrary field. A lack of these steps in the usual approximations yields inaccuratedynamics, for example, predicting faster dynamics and incomplete charge transfer.