Real-Time Time-Dependent Density Functional Theory for Simulating Nonequilibrium Electron Dynamics

Abstract

The explicit real-time propagation approach for time-dependent density functional theory (RT-TDDFT) has increasingly become a popular first-principles computational method for modeling various time-dependent electronic properties of complex chemical systems. In this Perspective, we provide a nontechnical discussion of how this first-principles simulation approach has been used to gain novel physical insights into nonequilibrium electron dynamics phenomena in recent years. Following a concise overview of the RT-TDDFT methodology from a practical standpoint, we discuss our recent studies on the electronic stopping of DNA in water and the Floquet topological phase as examples. Our discussion focuses on how RT-TDDFT simulations played a unique role in deriving new scientific understandings. We then discuss existing challenges and some new advances at the frontier of RT-TDDFT method development for studying increasingly complex dynamic phenomena and systems.

Nuclear–Electronic Orbital Time-Dependent Configuration Interaction Method

“…Real-time electronic structure methods are a natural tool for studying ultrafast chemical dynamics and molecular responses to external perturbations. − Real-time methods have additionally proven to be incredibly powerful for calculating absorption spectra, especially for spectra with densely packed excited states where time-independent methods struggle . By evolving multicomponent wave functions, where more than one type of particle is treated quantum mechanically, − real-time theory is capable of simulating additional interesting physical phenomena.…”

“…The most common real-time theory is real-time time-dependent density functional theory (RT-TDDFT) due to its reasonably high accuracy at relatively low computational cost. − ,, There are, however, many well-documented chemical motifs where RT-TDDFT and DFT struggle to produce accurate predictions . Charge transfer states, Rydberg excitations, and systems with inherently multiconfigurational nature all pose challenges to RT-TDDFT .…”