Molecular orbital theory in cavity QED environments

Abstract

Coupling between molecules and vacuum photon fields inside an optical cavity has proven to be an effective way to engineer molecular properties, in particular reactivity. To ease the rationalization of cavity induced effects we introduce an ab initio method leading to the first fully consistent molecular orbital theory for quantum electrodynamics environments. Our framework is non-perturbative and explains modifications of the electronic structure due to the interaction with the photon field. We show that the newly developed orbital theory can be used to predict cavity induced modifications of molecular reactivity and pinpoint classes of systems with significant cavity effects. We also investigate cavity-induced modifications of molecular reactivity in the vibrational strong coupling regime.

On the characteristic features of ionization in QED environments

“…( 3) can be approximated using one of the ab initio methods mentioned above. In this work, we mainly focus on two approaches: SC-QED-HF 56 and QED-CC 27 .…”

“…The SC-QED-HF wave function incorporates electron-photon correlation explicitly and provides origin invariant molecular orbitals. 56 This enables us to define a consistent Koopmans' theorem for QED environments. At the same time, using the definition in Eq.…”

“…54,55 A QED extension of the theorem has not yet been developed since a consistent molecular orbital theory for polaritonic systems was not available. Recently, we solved this problem using a new ab initio method called strong coupling QED-HF (SC-QED-HF), 56 which allows us to formulate a QED version of Koopmans' theorem.…”