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MO: Fachverband Molekülphysik

MO 6: Theory

MO 6.5: Talk

Tuesday, March 15, 2022, 11:30–11:45, MO-H7

Non-adiabatic dynamics within the cavity-Born-Oppenheimer approximation — •Thomas Schnappinger and Markus Kowalewski — Department of Physics, Stockholm University, Sweden

As shown by experiments, strong coupling between light and matter can be used to modify chemical and physical properties. In the case of a molecular system interacting with the vacuum field of a cavity, strong coupling reshapes the potential energy surfaces forming hybrid light-matter states, termed as polaritons or dressed states. In this way, it is possible to manipulate the non-adiabatic dynamics of the molecule and open new photophysical and photochemical reaction pathways.

A theoretical approach to describe such coupled molecular-photon systems is the so-called cavity-Born-Oppenheimer (CBO) ansatz. Analogous to the standard BO approximation, the system is partitioned and only the electronic part of the system is treated quantum mechanically. This separation leads to CBO surfaces depending on both nuclear and photonic coordinates. The interaction between different CBO surfaces can be formulated in terms of non-adiabatic coupling elements. In this work we combine the CBO ansatz with the complete active space self-consistent field (CASSCF) method, to describe the cavity-induced effects on ground and excited states as well as the non-adiabatic couplings. Based on the CBO-CASSCF results we perform nuclear wave packet dynamics to describe the non-adiabatic processes within the framework of the CBO approximation for a molecular-photon system.