Pushing the frontiers of modeling excited electronic states and dynamics to accelerate materials engineering and design

Electronic excitations and their dynamics are oftentimes at the foundation of how we use and probe materials. While recent experimental advances allow us to do so with unprecedented accuracy and time resolution, their interpretation relies on solid theoretical understanding. This can be provided by cutting-edge, first-principles theoretical-spectroscopy based on many-body perturbation theory (MBPT) and time-dependent density functional theory (TDDFT). In this work we review some of our recent results as successful examples for how electronic-structure methods lead to interesting insight into electronic excitations and deep understanding of modern materials. In many cases these techniques are accurate and even predictive, yet they rely on approximations to be computationally feasible. We illustrate the need for further theoretical understanding, using dielectric screening as an example in MBPT and faster, more accurate numerical integrators as a challenge for real-time TDDFT. Finally, we describe how incorporating online databases into computational materials research on excited electronic states can side-step the problem of high computational cost to facilitate materials design.