Speaker
Description
When light and matter strongly interact, polaritonic states with mixed electronic and photonic character emerge. As a consequence, new photochemical pathways become available under strong coupling conditions. In order to get insight on the mechanism underlying these modifications, theoretical studies using accurate ab initio methods are fundamental. In particular, Quantum Electrodynamics - Coupled Cluster theory (QED-CC) has been recently proposed as a suitable method to describe electron and electron-photon correlation. However, coupled cluster theory is known to provide unphysical complex energies at degeneracy points between states with the same symmetry.
In this poster, we explore how a quantized electromagnetic field can alter conical intersections and thereby modify photochemical processes. We highlight how the well-known numerical artifacts in coupled cluster theory can still be found in its generalization to quantum electrodynamics, and we propose a new parametrization that is able to correctly describe conical intersections between states with the same symmetry. This method, together with an efficient implementation of excited state gradients and non-adiabatic couplings, will allow to accurately study excited state dynamics in strong coupling conditions.
