Speaker
Description
Polaritonic chemistry involves a vast number of coupled electronic, nuclear, and photonic degrees of freedom, which limits the applicability of fully ab initio approaches. Here, we present a semiclassical simulation framework that self-consistently combines numerical solutions of Maxwell's equations for realistic optical cavities with quantum molecular dynamics at the time-dependent density-functional tight-binding (TD-DFTB) level. This approach enables atomistic simulations of large molecular ensembles interacting collectively with cavity modes, while mimicking experimental conditions. From these simulations, we can obtain cavity transmission spectra and identify polaritonic signatures, while also accessing local molecular responses that depend on molecular number, geometry, position, and orientation. Applying this framework to driven cavities under collective electronic strong coupling, we present a new mechanism of vibrational activation, whereby collective electronic Rabi oscillations coherently drive nuclear motion. The effect is maximized when the collective polaritonic splitting resonates with a molecular vibrational mode, and exhibits features consistent with a stimulated Raman–like relaxation process.