Over the past four years the Pavanello research group has developed an array of Density Functional Theory (DFT) embedding methods for the description of periodic and molecular systems alike, including their electronic and nuclear dynamics. The overarching goal of this effort has been to allow first principle simulations to approach realistic time-scales and length-scales, and to shed light on the dynamical behavior of complex systems. Our theory development has resulted in a new open-source DFT embedding software called embedded Quantum-ESPRESSO – eqe.rutgers.edu. When inspecting the electron dynamics of condensed phase systems in real time, we observe all the relevant regimes proper of non-Markovian open quantum system dynamics, such as electronic energy transfer, and screening. In addition, the ab-initio modeling of system-bath interactions brought us to observe and justify the holographic time-dependent electron density theorem. Real-time TDDFT embedding simulations show that non-Markovian effects in the electron dynamics of molecular systems are typically small due to their low polarizability and low coupling. Conversely, for molecules at metal surfaces, the non-Markovian effects are dramatic. Metals have large polarizabilities, and even in a regime of low coupling their effect on impinging molecular species is significant – line broadening, peak shift, and intensity borrowing are observed, characterized, and explained in terms of inter-subsystem dynamical interactions.

Spectroscopy of molecules at metal surfaces: Markovian and non-Markovian electron dynamics

253rd National Meeting (2017)

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