The aim of the project is to develop and apply methods and techniques to describe and investigate the complex time- and space-resolved dynamics of molecular-plasmonic hybrid systems interacting with external light fields. Interaction of such systems with external light fields leads to a complex interplay of physical processes: for the plasmonic system, the excitation of collective electron dynamics inside the metallic nanoparticles leads to strongly modified electromagnetic near-fields with complex polarization and spatial structure. Of course, also the molecular system could be independently polarized and excited, with induced electronic and/or vibrational dynamics. However, the combined system cannot necessarily be partitioned into two individual subsystems (molecule and plasmonic nanoparticle) as it features additional astonishing phenomena which only occur when both systems are in close proximity and may interact: the nanoparticle’s enhanced near field interacts with the molecular system and contributes to its polarisation and/or excitation. The induced dipole of the molecular system, in turn, interacts with a mirror dipole in the plasmonic nanoparticle, and this interaction will self-consistently modify the electromagnetic nearfield. Besides these electromagnetic (EM) aspects, the close proximity of the metal near the molecule modifies the molecular electronic structure at the quantum level (QU): new, charge-transfer states between the molecular and the metallic system may arise. These ingredients (QU+EM) lead to a plethora of new and exciting physical and chemical phenomena, such as the formation of new quasi-particles, new mechanisms for chemical reactions or the ultra-high spatial resolution and selectivity in molecular detection.
In order to model and investigate this exciting physics and chemistry, a combined description of the (static) quantum mechanical electronic structure of the molecular system in close vicinity of the plasmonic system (QU), the interaction with the electromagnetic field (EM) and also the induced complex dynamics of the hybrid system is necessary. Existing approaches to describe and investigate these complex physics and chemistry commonly focus on either an accurate description of the electronic structure of the hybrid systems or the electromagnetic properties of these systems. Only few approaches and works aim at a description of both, the quantum mechanical electronic structure and the simulation of the spatially inhomogeneous, time-dependent near field. And almost nothing is known about the field-induced complex time- and space-resolved dynamics of the hybrid systems – which lies at the heart of this project (QUEM-CHEM).
Besides being of fundamental interest, this interplay between near-fields and molecules is very promising for applications, potentially enabling revolutionary breakthrough in new emerging technologies in a broad range of research fields, such as nanophotonics, energy and environmental research, biophotonics, light-harvesting energy sources, highly sensitive nano-sensors etc. Thus, within this project, new approaches and methods beyond the state of the art are being developed, aiming at a synergistic description of existing but typically independently applied approaches and employ these to certain prototype applications and scientific questions in sensing/spectroscopy, plasmon-induced catalysis and the dynamics of new quasiparticles.
